BritishV8 Forum

Kevin was just talking about the Ford 4.6 pistons in the newbie thread. The Ford 4.6 deckheight is damn near the same as the Rover at 227mm (8.9370"). Interesting. You can also buy 94mm (3.7") pistons for the 5.0l version of this engine with stock piston height (1.210") or stroker height (1.190"). The stock stroke is 90mm (3.543") so the P76 crank (3.5") is a direct fit for the late Rover block using the stock Ford piston and the +.150 (5.85") early journal Chevy rods. Total displacement of 300cid. BITCHIN'

So on to the elusive 350 crank in a Rover block: The stock Ford 4.6 piston height is 1.210". For the stroker kits (3.75") the piston height is 1.190". That gives us some options anyway. So for the Buick 350 crank at 3.85" we'll need a +.150 SBC early journal rod (5.85") to come up to the stock 8.944" Rover deck height. I guess that would actually put the piston about 6 thou above deck. The block is probably going to need a decking though so we're looking at more like 16 thou above deck. Might be able to mitigate that by skimming only 5 thou off the block. This combo makes a 5.4L (331cid) engine that weighs around 350 lbs. Cool. Compression works out pretty good. Using my Buick 300 heads as an example (45 cc) CR is 11.6.

Another option would be to destroke the crank by, let's say, 50 thou using OS journal bearings. That leaves us with some room to deck the block more if needed; Let's say 10 thou. That puts the piston 30 thou down the hole. So we end up with 3.8" stroke and an overall displacement of 327cid. SWEET! Compression with this combo would be 10.2:1. Nice.

There are a bunch of companies that sell a 3.75" stroker kit for these engines too. Here's a source for the pistons. (just one I randomly picked):

http://www.dssracing.com/ProductDetails.asp?ProductCode=4824X

"5.0 Modular Ford Stroker 2V (3.75" stroke x 5.850" rod) Max Quench Dish, 1.190" comp hgt, -13cc, .927" floating pin, 1.5-1.5-3.0mm ring groove"

So they gotta make OS pistons for rebuild on these engines, right? Maybe not. Let's say we can get 40 over pistons though so we end up with a bore/stroke of 3.74" x 3.85". That gives us a finished displacement of almost 340 displacement.

Top this combo off with those bitchin' new heads TA is making right now and MOTORHEAD PORN! OMG somebody hold me back! aaAAAAhhhHHHH! oooOOOOHHH!! Ok Ok OK ok ok ok ok. Focus, Nic. Finish the engine you're working on now.

That was fun.

I failed to mention that the rod ratio for this combo is like Chevy 454 crap BTW at 1.52. Still bitchin' though. Just don't rev it above 5 grand! You might not have to.

Not bad Nic, not bad at all. And I can't see the engine weight being much over the 320lbs or so the standard Rover weighs either.

So what happens if we use a 300 block? (or the P76 Art is looking for)

Jim

Nick,

Rover deck height is 8.96" according to data I have and is the figure i used when building the 4.35.

Thanks for all the other info, looks like theres a few more options available to us Rover nuts!

 Those pistons from that vendor i posted are very good value though and make a simple upgrade possible at minimum cost.

Kevin.

Definitely 8.96" is better than 8.944". I'm not sure where I got that number. Maybe that's my engine after decking. Well an extra 16 thou works great. I reworked the numbers and I was 25 thou off. DAMN! with the stock deck at 8.96" then the combo of the +.150 SBC rod (5.8") and the stroker piston (1.190") it's at 5 thou positive deck. Oh well. I guess we'd need the piston tops to be skimmed a bit. Destroking the block to 3.8" yields 20 thou neg deck. That may be more desirable. Thanks Kevin. That's pretty cool.

BTW, I didn't mention it above but the CR's are based on the -13cc dished pistons.

OK the 300 block. Deck height 9.5". So we need another 500 thou. so... WAIT isn't the 350 rod like 6.4" or something? I'll go look it up...

OK They are 6.35"! Promising. Wait. The bore size is wrong. I have only found references to 30 over. I don't think anybody makes off-the-shelf 50 over pistons, let alone 60 thou. They're only taking these block out to a max of 40 thou and most guys won't do it. TOo bad. I was pretty cranked up there that we'd found THE combo for the 300 deck 390 lb. Buick 350.

Keep looking. I'm still buzzing after the first round. I am really trying hard not to start working on that engine.

I didn't say anything about the P76 block. Ok. Is the P76 block deck height 9.63"? The only reference I found was that it was 17mm taller than the Rover. That works out to 9.63".

If that is the case then in order to use the Ford 4.6 pistons (3.552") we need to find a 6.5" rod. WOW! The rod ratio would be 1.68. Not bad. Do you think the valve shrouding would bad with the big stroke? 3.552" bore x 3.85" stroke would yield: 305cid

I have no idea where we're going to find a 6.5" rod though.

Is that what you were asking?

Yeah, pretty much. Still looks like the 300 based 350 is the one to concentrate on though.

Jim

Nick,

With a P76 block you would have problems from stopping it splitting down the middle and a 52 thou overbore would be pushing your luck a bit.

Real Steel in the UK are doing a 5.0 stroker kit with forged pistons for £1500 so with out the VAT =£1300 = $2150 probably too much for you guys.

I was also looking at that Ford Modular 4 cam engine, the 5.0 version with a decent induction and exhaust would make an easy 350+ BHP but again it's money!

Kevin.

I'm with you there. I gotta admit it was sorta like uncovering the Holy Grail when it all fell into place though. A 350 crank in a Rover block with off-the-shelf parts is insane! I swear I momentarily achieved immortality. LOL

I love that Monster engine idea that Dan built but my only beef with it is the rod length. It'd be nice to have a little better ratio to work with. I realize the trade off is the piston stability but Ford's making it work.

I found a Buick 3.3 V6 piston 1.310 comp height. 60 over might work if they sell them. Looks like they only go 40 over though.

Can the 300 block be taken out to 3.8"? Then maybe we could consider those Supercharged Buick 3.8 pistons. 1.09" height. But then we're back to those elusive 6.5" connecting rods. The next two need 6.25" rods. Dodge 3.8 V6 piston 1.369. Ford 2.3L piston 1.33

For the P76 I found a 1.170 piston Chevy used in their 2.2L 4. They supercharged that one, right? So we're looking for a 6.53" rod then. LOL! Magic rods!

Maybe we should start with the rod. Buick 350: 6.35" and find a piston with 1.22" compression height.

Nick,

You've gone full circle, the oversize Ford is 3.7" and 1.220 comp height. LOL

I think in retrospect you could always have done something differently but you have to have worked with whatever was available at the time.

If I was to build an engine again it would be a different spec but on thinking about it I quite like what i've got, it's a bit different having 300 heads and with the big valves and bowl mods it give the flow i needed for the potential of the crower 50232 cam and thats whats important.

 I also quite like the relatively short stroke of the 4.2  77mm. crank as it makes for a sweet free revving engine but still has plenty of torque, the longer stroke engines don't seem to want to rev much over 5200 RPM and there was one UK Rover V8 specialist who experimented with strokes in excess of 92mm and the engine ran rough and wouldn't rev.

For additional capacity on Rover blocks the 96mm. top hat liner is the way to go, your pretty much into having wet liners but if the liners are left 2 thou proud at the deck you get the O ring effect so sealing is not a problem..

It's all down to what you want the engine to do, big bore, shortish stroke for all out performance long stroke any bore for a torque monster 4 x 4 type engine.

Kevin.

I'll say one thing, it's a whole lot better to have the engine actually in the car and running than having it on the stand waiting for custom parts to be made like mine is! Kevin, you don't know how I envy you right now.

I think the 350 rods are the way to go. The late model ones are the best and they are quite strong, and reasonably light. The BuickV8 guys have been going towards Hersche rods and Diamond pistons over the last year or two and it seems Diamond is quite flexible in making what you want. I used Venolia but after all the costs added up I think the Diamonds would cost less. All in I bet I was close to double the original quote of $75 a piston, whereas I've heard of $400 forged sets. So finding an off the shelf piston can sure make a difference, but sometimes the extra cost of getting exactly the right part can be worth it.

What it seems to come down to is either special rods, special pistons, or both. Luckily there is nothing exotic about what is needed so there are more choices. There are some NASCAR SBC rods available and sometimes you can find 6.4" rods, maybe even 6.5". But they are not production parts so either take-outs or expensive. Nic, I think you are on the right track though, with the 350 rod. It's long enough to give a favorable rod ratio so the engine can wind up. That's where the extra deck height of the 300 is a real advantage.

As far as having the piston protrude above the deck, that isn't a real problem unless it's more than about .020" because you can have thick head gaskets made. I have learned that the only significant difference between 340(300) head gaskets and 350 is that the 350 gaskets have the pushrod section solid and punched with clearance holes whereas it's all open in the earlier gaskets, but the holes are large enough to work on the earlier engines. So 350 gaskets can be used and 350 MLS gaskets are available in any thickness. (BOPR gaskets don't work because of coolant ports but these may work on BOPR) So if you're .010" proud of the deck a .050" gasket is just the ticket. Any more than about .020" though and you'll start seeing gasket issues at the intake.

On a .100 overbore: I doubt it'd work real well. I'm down to just a hair over .100" wall thickness in a couple of places on my 340 block with a .050" overbore (stock 350 bore size). That's a side wall and we were able to stay above .150" on the thrust faces, but for a street motor you'd really prefer to be close to 3/16". Dropping that down to 1/8" or below is getting a little risky. So while it might work out OK, you'd want a sonic check and might have to go through several blocks to find one that gave you enough thickness evenly distributed on the thrust faces. Still, if that was the only piston available...
You might ask the piston manufacturer what they would charge to make them undersized. Just a thought, you never know when there might be some scrap parts laying around that could be saved that way.

But wait, isn't the 300/340 a 3.750" bore? 3.800 for the 350? Yes. I just looked and that's correct. You can use the V6 pistons with no problem.

Jim

Ok peep this:

http://www.flatlanderracing.com/eagle-chevysb.html

They sell "Honda" rods for the Chevy. There are some at 6.25" so that with the Ford 2.3 "truck" piston (3.78") at 1.33" ends up at 5 thou above deck. 9.505". They also sell Small Journal 6.2" rods. That paired with the Dodge 3.8 V6 piston (3.777") at 1.369" puts the piston top at 9.494", a mere 6 thou below deck. A little block decking and we're golden. No need to cut the journal.

Those Dodge pistons have a 16cc dish in them. So with these and my 45cc Buick 300 heads compression is 11:1. Nice. With the stock 54cc heads it's at 9.9:1.

What's the final cc on those TA heads? This is doable, guys.


I forgot to include the displacement: 345cid (5.66l) with the stock Dodge bore. The rod ratio isn't terrible at 1.61. AND you've got a shorter lighter "350". COOL!

I suppose you could go all the way and use the "Honda" journal size to monster up the stroke to 3.96". Using the 6.2" "Honda" rod and the Ford "truck" 2.3 piston 20 over you'd get 3.8" bore x 3.96" stroke:

A 400 lb. 360cid (5.9l) Buick 300 with a very Chevy like 1.58 rod ratio.

Wicked. I wonder how long that would last. LOL.

Nic, I looked at Honda rods recently to see if the 340/350 crank could be de-stroked to clear the cam, rails, etc in an aluminum block. If I recall correctly, the journal sizes were something like 1.89" or thereabouts. That would enable a de-stroker crank of 3.75" or so. I seem to recall hearing that a tuner had welded a crank up to 3.75" to fit the aluminum block

Custom rods are an enabler for certain combinations like this and often turn out to be not that much more than well-worked stock rods.

That's true, you could use the "Honda" 6.3" rod with the Ford Truck piston at stock bore and you're at 336cid (5.5l). with a rod ratio of 1.68. The Buick 350 ratio. That's only 30 over on the block too. Good conservative idea.

In the Rover it's a bit tougher. Lets see... If we can use the Acura B18a rod, I'm pretty sure that's still 1.89" journal, we can get some that are 5.967". We use the full .110 thou destroke to 3.74". Using the stock Ford 4.6 piston (1.120) for a more favorable rod ratio of almost 1.6. Nice.

http://www.importperformanceparts.net/imports/eaglehrods_acura.html

Ok, so I'm, on-page, 350 sbb has same head bolt pattern as 300/340? Thanks, roverman.

Oop's, fergot, on "those" 350"sbb's, reportedly making 1,000 hp., stock/reworked cranks? Should we need, doubt-it, there's the sbf., raw forgings. Scat claiming 120 ksi on tensile. Thanks, roverman.

I've heard the SBF mentioned a couple times as a source for a crank. Does the SBF and SBB have same main spacing or something?

I think after the current engine is done I might take on the Rover "350". The math is just way too intriguing for me. I wonder how far out the bottom the pistons will go...

Hmmm, there's only 1.6 inches left over after the stroke is drawn on the Westwood flanged liners. That leaves the pins just bearly in the cylinder by about 100 thou. That would explain the rattly issues that Kevin was talking about. (That's with the 3.74" stroke and the 1.12" Ford piston) The piston lands are probably popping out the bottom and exposing the smaller diameter of the forged pistons till it comes up to temp.

That might be the caveat right there. I wonder how much room there is for longer liners. Is that why you were looking for them, Art?

Nick,

In case it wasn't a typo, the Ford 4.6 comp ht. is stated as being 1.220" for those forged 3.7" ones.

Kevin.

Oh shit. Ok. How did I get to 1.12?? I must have been really tired. I had been working for about 35 hrs. straight when I started this thread. I was board waiting for a render from our "farm" (processor array for processing movie frames). I was working on a rush job. I think you posted this a couple times. WOW it really didn't get through. LOL!. Thanks for goin' easy on me, Kevin.

I went back to find where I had decided the height was different. It was after a long time awake. LOL!. OK so scratch that last post about using the "Honda" 5.97" rod. with the magical 1.12" Ford pistons. Unicorns.

The best part was that I'd already done the math a dozen times.

Some food for thought, based on the 340 build.

OK, now here are the Venolia pistons:

MVC-887S.JPG

And here are the stock aftermarket replacement pistons:

MVC-744S.JPG

If you look at the pin placement, the Venolia has a 1.283" compression height and there isn't a whole lot of room below the oil ring. Bear in mind this piston uses thinner rings and this is also .750 wrist pin. On the other hand, these are blower pistons. The ring package could be moved up on a N/A engine. Also, the oil ring can extend into the wrist pin area if teflon buttons are used as they were with this build. In that case the buttons have a groove cut to match the oil ring groove. Also these were used with 7" rods to get a zero deck. (actually .005-.008" above the deck depending on piston rock)

Both engines had very similar compression 10-1/4 stock I believe vs 10.6 with the new rods and pistons.

Jim

They sure had a lot of metal on those old pistons... Those Venolia pistons are custom, right?

Yeah, totally. They quoted $75 each but by the time we added pins, buttons, etc,etc,etc it was over $1100 for the set. I think you could do just as well with Diamond and at a lower price.

Jim

Guys,

Just for information, the longest stroke crank for the rover block produced by John Eales (JE Developments) is 91.5mm/3.602" for a capacity of 5298cc with 96mm./3.779.5" top hat liners. Not cheap though!

Kevin.

So let's see, a little math here and, voila! The 340 crank at 3.85" comes in at 97.79mm, but it has much larger mains. Of course those can be cut down, as can the bob weights, to make it fit the Rover block. I think it already fits the 300 block if the mains are cut down a bit. I have no idea what you could do with rod length in the Rover block, but let's say you went with a custom piston, made the ring package short and near the top, used teflon buttons and put them up into the oil ring and used a small diameter pin, you just might get a decent rod ratio.

Jim

Buick 215 deck height is 8.96", right? Half of the 350 stroke is 1.925". Half of a destroked 350 (taking 0.100") is 1.875". That leaves 7.085" for rod and piston. I'd pick a custom Honda rod with about 5.7" of length and that would leave 1.385" of deck height and allow for a reasonable ring setup.

The question would be, how far out of the bottom of the cylinder does this piston get pulled?

If crank/piston interference is too much, a longer rod might help that. That's a trade-off between piston rocking in the bore because of a too-short compression height, and piston rocking in the bottom of the bore because it got pull out too far.

Are the oil pans of the 215 and 300 similar? Clearing the oil pan was one of the issues with the stroked 300.

De-stroking should help with cam clearance.

That's a 289" engine, right?

The Westwood flanged liners are 5.34" long. SO the piston will be sticking out the bottom. With a destroked crank (3.75") there is only 1.6" left for the piston to be inside the bore. That means the pin will be pretty close to coming out too. YIKES! And a little cool.

Longer sleeves would help.

I do have to say that the 5.7" rod would work but the rod ratio is not very good. I think it's pretty close to 1.52 but an engine like this would not be meant for high powerbands. The only rod ratio I've seen that's worse is the Chevy small block 400. I think its like 1.48 or something. Putting the pin farther up the cylinder would help.

Isn't the SBC 400 using a 5.66" rod? That's a stroke of 3.75" too.

BTW, where were you able to find a 5.7" "Honda" rod?

The 'Honda' rods would have to be custom. I'll have to look again at the various rod maker's lists to see if that's even a possibility.

You are right about the longer sleeves. That must have been what Mickey Thompson did to make that 289 boat engine. I can picture longer sleeves that are profiled for clearance from the crankshaft.

Not a practical solution. Rats.

I'll redirect my attention to a more typical crank for stroking an engine. Sounds like the tried-and-true 300 crank is the deal. That, or just go with a 4.6 crank in my 4.0 block.

OK, I'll confess I don't understand the fascination with destroking anyway. I get it that the honda rod has smaller journals but I'd be inclined to go the other way with that and make the stroke longer, not shorter. Plus it can't help with crank strength to cut down the rod journals that much. But then again, I'd just go with the iron block. It's not that big of a weight penalty.

Jim

LOL. The only purpose would be to make it feasible for the Rover block. The answer is, yes, the iron block is probably the way to go but for the sake of fleshing out the complete concept it's worth it to go through the process.

I'm with you on the going the other way. That's why I liked the 360 idea:

Quote...use the "Honda" journal size to monster up the stroke to 3.96". Using the 6.2" "Honda" rod and the Ford "truck" 2.3 piston 20 over you'd get 3.8" bore x 3.96" stroke:

A 400 lb. 360cid (5.9l) Buick 300 with a very Chevy like 1.58 rod ratio.

I think that will be the next engine I build. That would be fuckin' sweet!! On the journal size. It's true that the crank strength would be changed but the Chevy guys are doing this all the time now. Probably with forged cranks. I hear the "ArmaSteel" cranks are pretty strong though. We'll see how it works out. I'm totally willing to take a risk. I think it will be fun.

Do you think we'd need a block girdle for the mains on the 360 idea?

Has it ocoured to anyone... "The further "out" we go- the tougher to return to Planet Earth"? Drag racers been using "deck plates" for stroke increases, to achieve a good rod ratio, long time. I feel  deck plates/adapters, may be best way for Lotus/Rover build. This would allow 3.85"+strokes with good rod ratio and no rod/cam bumping. roverman.

Well... if someone could figure out a way to keep a P76 block together....

Greg

Art - any idea as to when you're going to start your lotus/rover hybrid - that is VERY interesting?

Greg, It's called welding. Probably diminishing returns compared to much more readily available 4.0/4.6's. Tony, just because I can, does'nt mean I should. Kind of one-off project, if ALL went well, I could probably make 50c/hr. for my labor. Probably more sensible to design/build a better hemi head for the Rover. Much better overall potential. roverman.

Don't get pissy, Art. LOL. Seriously, is welding enough? I don't know the P76 block well. I know the Ford small small block needs lifter girdles from splitting in half. Then again that's with 800hp on vapors.

OR are you saying go ahead and break it then fix it with welding?

If you look at the ribs and such in a TA big block you'll have a better idea of what is needed. The lifter area is weak and will flex with a high lift cam. A girdle plate of even just 1/4" steel would help considerably with the bottom end. There is a lot of differing opinion on how that should be done and a thread on the V8Buick forum about it. Very likely the TA heads will breathe as well as the 4 valve heads and for less money. There isn't a bigger stroker crank than the 340/350 readily available at affordable prices and they will work with the cam in the block. Higher ratio rockers and/or a roller cam will get you the lift you want.

Jim

LOL!  Yeah Art, is it possible to weld alloy braces across the valley of a P76 block and have no resulting issues?  Enquiring minds want to know.

Greg

For the sake of notes on the 360 Buick stroker, here's the Ford "Truck" pistons:

http://www.kb-silvolite.com/spistons.php?action=details&S_id=435
http://cgi.ebay.com/ebaymotors/NEW-SILVOLITE-HYPEREUTECTIC-PISTONS-FORD-2300-4cyl-_W0QQitemZ290366397952QQcmdZViewItemQQimsxZ20091104?IMSfp=TL0911041910007r37886
http://www.summitracing.com/parts/UEM-3185H-5MM/

I'm pretty sure the "5mm" means .5mm (.0197) over.

Jim - some THOUGHTFUL comments on your part regarding T/A heads marketing strategy over on the V8Buick forum - why in the world would a company NOT do a cost/marketing analysis PRIOR to developing a new part!

Sir Art - I shall chip in .51/hr towards the design of that Rover HC/H (height-challenged hemi) Head - and because I'm such a big spender, please don't take your time.


Humm...dreaming out loud...get several of these related forums to come together for a Buick/Rover head design fundraiser - starting price point $1999 - they wouldn't collect dust!

.....and it looks like (a few V8 forum posts) there may be reason why RS hasn't provided any flow numbers for their heads - time and testing will tell.

Nic and  all. No, for using deck plates on 4.0/4.6 and getting piston where it belongs and good rod length for-say, 4 valve heads? roverman.

Nik-nixed, your getting my "underalls"-well-pissy. Wer'e one to measure lifter boss wall thickness on P76, they would find it's thicker than 215's, and comparable to sd-1's. I was yakin the "weldability" of BOPandR's.I  think welding "before" the block get's room-addition is "better"-Nic. Welding will probably slightly distort lifter bores,(they need bronze bushings anyway) and possibly cam tunnel, depending how "good" you are. Jim, all. Lotus heads with cams, towers and covers run about $100-$300 ea. I mite be off here, but I don't see the TA outflowin the 907 in a 3.7 bore, especially @ .45 lift. Unless the Lotus heads, kocks my sox-off, I see it as a one-timer. roverman.

I was reading about Cliff's stroker project again this evening and something else popped into my head. We were talking about offset grinding the 4.6 crank to get 3.4" stroke. Basically the 300 stroke with the native crank. Smart. I actually didn't think much about the journals in the late block being bigger in dia. till the other day when we were posting about it.

So then the thought occurs to me if the 6.0 "Honda" rod is used, 1.89" journal; The 4.6 crank could be offset ground to 3.525". Paired with the Ford 4.6 stroker 1.190" tall piston and that ends up with the piston only 7 thou below deck. Bitchin'! Just deck the block by 7 thou and that puts the piston at zero deck. Nice.

That would be a solid combo. Displacement with the 30 over Ford piston (3.73"): 5047cc. 308 cid. The 1.7 rod ratio is perfect.

That almost makes me waffle on building the lightweight Buick 360 cid. idea.

Yeah, I like the idea that a 4.6 crank can be used without a custom flywheel. I've got a complete 4.0 engine and I wrestle with the idea of stroking it with an offset ground 4.6 crank.

You just made it worse. ;)

I found a website of a boneyard that sells Rover parts, including cranks. $300 for any 3.5, 3.9, 4.0, 4.2, 4.6 crank. Stroking gets the biggest return for the expense.

OK you "strokers", I'm thinkin the bottom corners of rods are bangin the cam? How bout VW "style" with stud in cap and nut, or cap screw on top? Leaves more room in there. "Slim chance better than no chance", roverman.

Use the late capscrew style 350 rods if you can.

Jim

You're saying that the heads on the rod bolts are hitting for the 3.95" stroke, right?

With that stroke it will be hitting the block in several places or is there a lot more clearance in the 350 block I think you must be talking about, with all the different combos we;ve discussed am getting confused.

Kevin.

I'll defer to Jim there. My assumption would be it's very similar to the 350/340 block on the very bottom. Well, for the sake of feasibility, That stroke will pull the pistons right out the bottom of the sleeves. So, no go, either way... Well I guess unless you get longer sleeves. It's gonna be tight!!

Nic and all, This 3.85+"stroke/oem. Rover block thing is looking like , diminishing returns? I agree with Jim, if you want the mega strokes, use the block designed for them(350), with a proven track record and much less effort. If you "must", I suggest the P76 block or aluminum deck plates with liners through them.Good Luck, roverman.

I feel ya. It's more a thought experiment than a real possibility. I'd prefer to offset grind a 4.6 crank to 3.5", or build the "short" 360 we talked about. With that one the possibility of smacking the cam with our larger base circle roller cam is a pretty real issue, I guess. I don't know how close it is in the 350 as it is with 3.85". Anybody know?

Nic ol' chum, cut to the chase! Get that "Wildcat" 4" bore block with "raised cam"-matching elevated price, TA heads, any ol' stroke you want and WOW us! Cayman account? roverman.

LOL! Done.

Until that happens-Nic., I'm "peepin" that, I-beam, 4340 billet, 2.1"x6",sbc rod from "KMJ"-thanks to Nic. Approx 1k hp. rated for $330 and only 610 grams-before I narrow it !  China-huh. Different Strokes-folks, roverman.

Nic, I seem to remember a Silvolite catalog where a fella could look up pistons by their bore diameter. Do you have any other sources?

Reason I ask is that I was high (only) bidder on a Rover 4.2 crank. I thought it would be pretty trick to use in my Olds engine. Obviously, I hadn't thought it through. If I do that, I'll need pistons.

If my math is right; 8.96" deck height, 1.515" throw, 5.66" rod, I need a piston set that's ~3.500" bore, with a 1.785" deck height.

I looked at summitracing's page and could not find anything with a compression distance of 1.785", but a few with less distance. Maybe some longer connecting rods to compensate, or go with custom pistons from perhaps JE or equivalent manufacturer. It is probably not going to be cheap though.

Hey Paul. I think this will be a cool mod. You'll make what... 240ish? Sweeet. Here's a link to a Silvolite page I've used a lot:

http://www.beckracing.com/silvtoc.htm

Looks like a late 70's Buick 3.2 V6 is the piston you're looking for. 1.78" comp height. Should work great. I doubt there will be any thing other that cast but you should be fine with that.

Brilliant! Amazing, that piston is perfect. I might have to go with Chevy rods to get a better pin fit, but it's so close that it will work fine.

Thank you.

Paul, you might want to consider the merits of a longer rod? More "burn" time, reduced "I" loads, easier on cyl. walls, cheep insurance  and fits the zillions of sbc. piston combos avail.? roverman.

Art, I always appreciate your excellent advice.

I'll check out the prices of the 5.85" and 6.0" Chevy rods and compare that to the cost of working up the rods I have on the shelf. I've got some 283 and 327 small journal rods (they are only slightly different). If they aren't already rebuilt on the big ends, I may opt for some custom rods. Piston selection gets easier with the 5.85" length rods.

The rod ratio is pretty nice at 1.86:1 with the stock rod, though. That's pretty good.

I'd prefer to use the stock rod because it would be less work and less money.  But the pin size on those Buick 3.2 pistons is .9398" and the pin size on the stock Olds rods is .875". I don't know much about boring out wrist pin bores, but I was guessing that boring the stock rod pin bores that much might not be a good idea. Would it work?

I just assumed that boring out the Chevy rod pin bores (.927") was not as risky.

I'm not crazy about the dish on that piston, 9.5cc, and I would have preferred a flat-top with notches for the valves, but I just figure I was fortunate that Nic was able to find something that was going to be close enough to work.

The 4.2 crank is costing about $80 including shipping, maybe a little more. It might need to be turned. The pistons are stock-type, so the cost of that would be a wash. So, it's just a matter of modifying a set of stock Chevy 327 rods while they get rebuilt. Not bad.

Edit; with a .030" oversize piston, displacement would be 237"/3.9L.

Ok. good point. I didn't think about the pin dia... OK so let's say you use the 5.85" (+150) SBC rod with the Chevy 2.8L V6 piston. The pin dia in the piston is only .905. Bore that out to .927 and you're good maybe.

The one I'm talking about is the #1478

Gentlemen, If  #1478 takes a floating pin, probably better to bush rod to .905" pin size?  Reaming out piston pin bores is a "precision" job or the piston becomes an ash-tray. roverman.

Nick/Art,

You might like to read this article by a certain Mr. Iskederian which covers the issues of rod length and cam duration. intersesting, controversial?

http://www.iskycams.com/techtips.php#2005

Kevin.

I think he's correct in that you will not change the output of the engine by changing the rod length alone. Another thing I agree with him about is that an engine is setup the way it is and there are some things that are just going to be the size they are. That's true for us too. I'll get to that. I also agree about the assertion that  long rod ratios are meant for low end torque motors. The piston speed at TDC of a short rod ratio is better for that.

I did think it was funny that he started out arguing that rod ratio doesn't make a difference and then countered with a story that it does. LOL! Seriously though, I'd love to sit down and have a conversation with him and some other guys of his generation that were there when all these ideas were being formed: Crower, Edelbrock, Burt Monroe. That would be cool. I'd ask Crower why his LCAs are so wide. I do appreciate Isky's argument that the piston sitting at the bottom of the stroke is better for sustained cylinder filling but this is why it's better for low end torque.

I think he's starting out his article with hyperbole to make a counter point that you are not going to unlock secret power by changing rod ratio alone. What we build in an engine is a system of cooperating components. In our case we are pretty much limited to what Chevy guys would call impossibly small bore size to start with. SO we are limited in our ability to increase valve area. With that in mind short rod ratios are going to hamper what we have to start with. I'm talking about monetary feasibility as well as mechanical and expertise. My point is the rod ratio should work together with the other mechanical functions of an engine to be optimal. The point is, the engine he described is one way to make power. What you need to do is optimize the cam to... Wait a minute. Is he selling me a cam?! LOL.

To use his example as a point that rod ratio is an important cooperating factor. The engine he describes NEEDS more duration to MAKE power on the top end. And he's right changing the rod ratio alone without changing anything else would likely yield no benefits. With our engines, considering the bore limitations as well as the limits of our head castings we have to keep these factors in mind when considering rod length. If we had room for massive intake ports we could get away with shorter ratios as well.

The last thing to consider is engine longevity. Piston side loads and shear are factors to consider when building an engine to last. Just sayin'. In conclusion I agree with him. Rod ratios do matter but are not solely responsible for the creation of power in a 4-stroke engine.

Yes, I would one day like to know, half of what "Ed" has long since forgotten. I wish he would have opened that can-o-worms called,"wrist pin off-set". OEM.pistons, uses them almost exclusively. Aftermarket, especially forged,NO! I suspect they don't want the bother and not enough request? As I was taught, decades ago, correct off-set reduces latteral thrust on cylinder walls, reduces piston rock at turn-over and reduces "I" loads and ring flutter potential because rod and piston doesn't completly stop at top,(crank pin past tdc. while piston is not). I defer to my previous post that, not once ,did I elude to greater hp. and torque. I was expousing "some" of the merrits whilst "juggling" for a "combo" of parts to fit a particular build. I suggest a read of all of "Ed's" tech wisdom, especially of that dreaded, .842" flat tappet, maxed-out at .007"lift per deg. vs. rollers. My vote isn't cast as of yet, for oem. hyd. rollers, as I eagerly await for qty. 48 en-route. Time will tell, roverman.

Gang,

The 4.6 has a rod ratio just a hair north of 1.8 - what's the effective ratio with the offset?

Also, does the 4.0 have wrist-pin offset?

Gudgeon pin offset fpr both 4.0 & 4.6 is 0.6mm.

kevin.

To put this in perspective, I believe 305" sbc/oem is 3.175mm.(.125"). Unless I was snoozin in class, I don't think off-set changes the rod ratio. I would like to see the formula an engineer would use to optimize off-set for a given build and how it changes the "I" load at turn-over,  roverman.

Mr. Isky didn't mention that silly-long rod ratio,(well over 2/1), that "Smokey" used in those 203"?, sbc's for Indy? Smokey wanted mega-long sqeeze time. Why? Slow burning combustion chambers, slow burning fuel(Methanol) and Turbo's. They ran pretty good for "Detriot wonder metal",cast iron stock blocks, once he deep-sixed the carbs. roverman.

My forged pistons have the stock 0.040" offset.

Jim

Jim, brand? For 340" sbb.? roverman.

Opps! You already said ,Venolia-right? They gave you the off-set option? roverman.

Oh yeah. For what I paid them I could have had them engraved if I wanted. (...for a small additional charge...)

Jim

Jim and clan, while speaking of sticker shock. CP Pistons gets $94.ea., base price for a flat top sbc-305 piston,2618 material. Pin off-set is $6. ea. Pins and clips are extra.Coatings extra. Since it's just a serious put-put, Rover, for the Huffaker, I'm goin with KB 832's in +.03", with pins, inserts/clips at $43. ea. and sort-of move the valve notches. Not my first choice on comp dist.-1.265" but not worth $94. each just because. Nic, your piston?

Art,

"KB 832's in +.03"

Can a Rover be bored that much safely (3.766 + clearance) or are you going to re-sleeve?

Carl,resleeve- Abalutely. Most o' the so-called, "experts", claim .020" os. is "it" on std. Rover-slip-n-slide-sleeves. I got (3) sets of "FSY3780SFM" from Wildcat. Here's how it works, Their made in Japan by Tsubaki,(best noted for good roller chain). Their boxed and distributed By ACL(Aussie),retailed by Wildcat(Wales) and then ,"maybe" sent to "us/Us"(5 mo's later). I'm thinkin they have a"lot" of miles onnum, before they ever get installed? There's "got" to be a better way ! I say, buy US. aluminum and keep your Rover,"pure", except for the made in England part, right Nic'...? roverman of dissent.

I'm definitely looking into alternatives. I'm hoping to have somethings to report in a week or so on that front. I'm still working out the details of using the 350 crank. It could be that by using the "Honda" journal at 1.89" it would help the cam interference issue. I don't have measurements between the rod bolt heads yet but it could afford more room for modification for clearance.

It could be that and a bit of destroking would do the trick to keep away from the cam. I'm not hot for the destroke idea just because if I'm gonna try to put a gigantic crank in here anyway I might as well try to make it as big as possible.

I'm concurrently working on the 4" bore thing too and exploring a potential solution for us there. With that in mind then I was looking at Manley's 1.05" height SBC forged pistons that coupled with the SBC "Honda" journal 6" rod and a slight destroke of 3.82" would yield a zero deck piston. Another option is JE pistons' 1" SBC forged piston with the "Honda" rods and retain the stroke for a piston deck 20 thou down the hole. That feels a bit better to me but the cost is another couple hondo$$$. Might be necessary though.

Nic' and clan. Since your building an "out-there" motor anyway, AND using a custom roller cam..."maybe", you could go up on the cam bearing size allowing off-set boring on the tunnel ? U-no, up and away from rods? Kinda like what "Wildcat" does, only cheeper? Put a (3) bolt, sbc. drive on front of cam and sbc gear or belt drive. roverman.

Good idea, Art. Do you think there is enough metal for it? I think we went through this when discussing whether to make them all the same size, right?

Reviving an old thread. Reading this got me inspired again to go ahead with the stroker project that's been on the back burner for a while. So tell me if my math is correct...
Ford 4.6  3.7" flat top pistons 1.220" comp height
Eagle 6" Chevy rods
JE Rover 86.36mm (3.4") stroker crank
Merlin heads with 32cc combustion chamber
Rover 4.0 block with 8.96 deck height
So with this setup the piston is .040" shy of the deck, is that ok? I figured the compression ratio to be around 12.74:1 even with the gap, assuming that the volume of the combustion chamber is 32cc, volume of a .048" head gasket 8.5cc, and the volume of the .040" gap from the piston to the deck is 7cc and the volume of the cylinder is 599.16cc and yields a rod ratio of 1.76:1. I'd like to get the compression down closer to 11.5 -12.5:1

Most factory Buick engines used a dished piston, which gave about a 3/8" wide squish area around the outside. With the squish distance held at .040" (zero deck and .040" head gasket) the CR was determined by the volume of the dish. With double that dimension your squish will essentially be ineffective, but depending on your piston crown thickness you might be able to machine a dish into the top to get the CR you want. Going that route, you could then deck the block/heads to get the proper squish dimension. Of course, custom pistons are always an option, I understand Diamond has some of the better prices.

JB

Justin, "JE Rover crank with 3.4" stroke", sounds pricey.Stock 4.6L Rover crank can be "off-set" ground with 2.00" journal to provide same stroke,(cost about $250.00 labor ,by a top rated shop).As Jim says, .08" squish thickness will be ineffective. Decking the block, probably necessary anyway, and a thinner gasket should get it to a reasonable dimension. Have you looked at "Icon" forged 305" sbc pistons ?  The Merlin head needs "chamber" work, to make it more effective, mine arrived at 37cc, for a 3.75" bore. Good Luck, roverman.

The JED crank is round about $650 before shipping but if I can offset grind a 4.6 crank I'll do that. How would one retain a 2" journal while offset grinding by what I would guess is around .08"? I know and have thought about using honda journal SBC rods that would give me about .11" to offset grind and a 1.88" journal size.
Thanks for the tip on the pistons, they look like a much better fit than the Ford pistons. Would I be able to use these in a stock bore 4.0 block? That is is there enough liner to bore to fit?
One more question, I have a set of 300 heads and have been quoted between $1.4k-2k to install oversized valves, seats, bowl porting, and a set of oversized valves as well as $2k for a set of Merlin heads delivered to my door I'm wondering what would be the smart route? A set of brand new heads or some worked 46 year old heads? I would assume that the combustion chamber design on the Merlin heads has been updated to a more modern design than the old 300 heads and would offer some advantages over just sheer flow #'s of the worked 300 heads.

I was surprised at the price you mentioned for the 86.36mm. crank, appears John has reduced his prices and of course you do not have to pay the VAT.

The 4.0 & 4.6 have 2.5" main bearings so i belive you can offst grind a finished crank to fit the earlier 2.3" main blocks or offset grind an unfished casting to maintain the 2.5" main bearing for the later blocks.

The cost for headwork to the 300 heads sounds a bit pricey even to me in the UK, if your using the normal upgrade size 1.63" in 1.4" ex. valves then the existing seats can be cut to size which only leaves the 3 angle valve job, opening out the seats and the area under the valves and then blending into the bowls, for road use I only cleaned up the port runners to maintain good fuel suspension as the ports are at least the equivalent of stage 3 Rover heads.

The standard deck height in the rover is 40 thou. so with thick 47 thou.composite gaskets you get very little squish especially with the standard rover dished pistons.

Re Merlin Heads, Real Steel sell direct and retail for £1315 inc. vat so net £1119.15 x $ @1.58 =$1768 + shipping etc.

Heres their catalogue and price list.       http://www.realsteel.co.uk/section1.pdf includes some pics of merlin heads.

Kevin.

What valve and spring combo are you using for 1.63" in 1.4" ex?

Justin,

If you mean which springs, that will depend on the cam, I'm using a Crower 50232 which recommends a double spring set up, but as I set a rev limit of 5800RPM I felt comfortable using a single spring, one coil less than standard with just slightly less seat pressure and  I used the buick 300 valve retainers caps which are stronger than the later Rover ones.

The springs are the DW060 in the Real Steel catalogue. they do duals DW520 I suspect that both these are US sourced anyway.

Kevin.

What brand valves as well

Justin, Stage I V6 Buick, are largest valves to fit the standard 1.660" centerlines.Seats MUST be changed. Shop I use gets $10. ea., labor and approx. $5 ea./seat. Ferrea and Manley have the valves. I suggest Comp Cams cat. for best "Behive" springs for your application. If the heads have a corrosion problem, bowl porting will help make"sprinklers".Good Luck, roverman.

May I make a suggestion? There is much to be gained and very little lost by the use of a 300 cast iron block, especially if you fit it with a 350/340 crank. At that point you have a 5.6L engine or with a .050" rebore a 5.7L and you also gain the considerable advantage of a great deal more strength in the threaded bosses which is a stupendous advantage in high output engines, aside from which the entire block is much more rigid. What does it cost you? Maybe 80 lbs. It could be less my memory isn't the best, could be 60. At any rate, for practically any application that much extra weight on the front end of the car is not going to be noticed at all but the extra displacement certainly will, and the extra rigidity means it will hold up better and longer before the next tear down becomes necessary. Plenty of head/intake combinations are available and if you are considering a $600 crank I would recommend the stock 350/340 crank instead and put that money into forged pistons which can be had for around $700. With Merlin heads and Willpower intake it would make an absolutely killer engine for the MGB, and the new TA heads would be even better if you can afford the time and money to get them.

JB

Justin,

As Art said you have good sources of valves in the US although using the valves I mentioned means you can retain the existing seats.

Don't know the brand of the valves but they are what everyone in the UK uses for stage 3 heads but not for circuit racing if you want much more than 6500 RPM.

Kevin.

Jim, I already have a 4.0 block and it appears that I can get several varieties of forged pistons for less than $700, although not with out some issues. I was considering a $600 crank but it appears I can use a stock 4.6 crank to meet my needs. If I really was going to be sane about the whole thing I could probably just pick up an LS1 off of craigslist for a little more than the price of some Merlin heads and have a bunch more, less stressed horsepower and a lot more time to drive it but I like the projects and, as foolish as it sounds, I'm committed to an aluminum block...

Justin and clan, One the of the great things about this forum,"diversity". Very little negativity for going non popular routes. One thing we all agree upon, our LBC's are worth it. Good Luck, roverman.

Art , can you forward me info on shop you use for valve and head work?
Thanks

I see that the stock intake valve head diameter of the 300 is already at 1.630", do you think that I could go to a 1.710" without replacing the valve seat?

Justin,

 The 300 inlet is 1.625" you would need to measure the size of the insert to see if there is enough meat to cut them to the larger size.

The exhaust valve is 1.312"

Also unless you are going to full race spec on the heads then there is no need to go to the larger size and it will probably cost you power.

It is a fallacy that fitting the largest valves possible will give more power.

Check the lengths of the larger valves, they may be longer but this can help  with the rocker geometry.

Kevin

Kevin
What do you have to support your statement that fitting the largest vaves give more power is a fallacy?  Just curious.  I'm getting ready to drop some major cash having 1.775/1.5" intake/exhaust valves and porting on a set of 300 heads.  per Dan Jones school of thought.  I realise you don't make low end power but horse power is horse power isn't it.  Talk me out of it please!  Heh Dan.

dave bash

I'd like to be able to add some larger valves with out having to replace the seats. The 1.4" exhaust valve sounds like a good solution but the 1.63" is basically the stock size for the 300 head. It would be great is a 1.71" valve would fit without replacing the seat, although then there's the length...so many variables... :-/
Dave what valve & spring combo are you using and, if you don't mind, how many buckets of cash do you think this is going to set you back. I'm just curious if the estimates I've gotten to do the same work are realistic, high, or low.
Thanks

There is an argument against fitting larger valves when it involves larger seats, but that has to do with increasing the potential for cracking between the seats. As for larger valves sometimes costing power, that could happen possibly, but only if the system is optimized for the smaller valves.

JB

Also depends on the chamber design as with a rover/buick chamber shape the valve head can become shrouded and you can end up with reduced flow until you get to approaching max cam lift, resulting in an engine with poor torque at low RPM.

You will often get better results from using a smaller inlet valve with carefully optimised area just below the valve head and correctly sized runners.

If you look at the chamber design of the merlin heads you can see how the low lift flow has been enhanced by the chamber shape which has been proven by the dyno testing where they produce a strong almost flat torque curve from above 2000 RPM.

Kevin.

After doing a little research on the web I found some oversized valves that may work without replacing the valve seats. VW 2.0 type IV valves are 4.606" over all length,  in 1.65" head, ex 1.41" head, and 5/16" stem. The exhaust may be a bit large and if so I could go with the 1.4" size listed on multiple performance rover sites in the UK, or, if possible, turn the valve down. The only problem I see mixing the in and exh valves  brands is keeping the springs, retainers and locks consistent across all the valves. Does this seem feasible and a more economical route than going the full tilt jumbo valves and seats?

Justin,

Are the VW valves the same stem size as the rover ones and are they waisted stems as per the rover big valves?

The difference in area for the inlet is relatively small, just wondering if it's really worth all the hassle.

Kevin.

I'm not sure if they're waisted but the intake is 1.65" instead of the stock 300 1.63" and it turns out that I can get a 1.4" exh valve. Seeing that I have to replace the valves regardless I might as well go with the biggest valve I can get without replacing the seats. If they're not waisted might be the deciding factor, although how much smaller is the waist than the stem and what is the stock rover/buick stem? The VW stems are 5/16" and the Buick v6 stems are, I believe, 11/32" and the stock 300 valves may be up to  3/8"... so how much would be lost going to a non waisted stem that's  between 1/32-1/16" smaller in diameter than the stock stem before the waist?
There is also a 1.73" option but that would probably mean new seats.

Just sizing up a 3.9 build for the dragster, hows this for a stock parts line up. Stock 2.8 stroke, 6" SBC rod and a stock dimension 305 piston, gives 8.96 deck less 1.4 or stroke less 6" for rod and 1.54 compression height for a piston .020" in the hole, some manufacturers use 1.56 compression height for a zero deck. For a stroker option we would need 3.4 stroke to use a stock 5.7 chevy rod. More food for thought.

Alan

Another valve question...Where would the biggest gains in flow come , a .020" larger valve head (1.65" vs 1.63") and no waist on the stem, or stock head and a waisted stem?

Justin, good question for a flow bench savy person like Dan Jones. My experience,(limited) ,leans towards the "shape/angle" of the valve more than +.020". Concentrating on low-mid lift enhancement, will show more rewards, for a street based motor. Stroking a 215/Rover by 1.05" will produce a bad L/R ratio and high side loads on cylinder walls. Alan,"for the dragster", how would we offer suggestions to this ? Good Luck, roverman.

Art, by "shape/angle" you're saying that I'd be better off by using a waisted stem?
As far as stroking the engine the combo I've come up with is using Icon IC835 chevy 305 piston (thanks for the suggestion) with a pin height of 1.133", 6.125" chevy rods, and  a 4.6 crank offset ground to 3.404". That gives zero deck clearance, rod ratio of 1.8:1 and a displacement of 299cid.

Justin, The 5/16 stem VW valve is probably close to 11/32(waisted) dia. Is it long enough ? I know of no flow spec's for your valve, in a 300 head. Nearly all int. valves benefit from a 30 deg. back cut. Exh.-no, but want a carefully blended radius on chamber facing edge,(helps air flow over edge)FWIW, sounds like your heads, as described, will flow around170cfm. on intake side. Should equate to a warmed-up street motor. Are you installing flanged liners ? Otherwise, 3.736 bore in std. liner, might be "iffy". Good Luck, roverman.

The over all length of the type IV vw valves is 4.606" and looking on a couple of UK site the rover valves  are between 4.595 and 4.612".
I'm not installing liners...that just puts the overall cost out of the fun to $ ratio. When you say iffy what does that mean, that is what are the possible consequences of trying to to go .040" over? The other possibility is to use the Ford 4.6 pistons with a pin height of 1.22"(3.7" bore), 6" chevy rods, 4.6 crank ground to 3.48", but the rod ratio is not as good @ 1.72:1

Justin, To put this in proper prospective, 400" sbc's have a rod ratio of approx 1.45/1. I would use 1.72/1, if the combo worked-out. Good Luck, roverman.

Art, That combo is probably the best best and least risk, I just like the chevy 305 option better...better rod ratio, don't have to rebush the small end of the rod, but the pistons are just too big :-/
More valve questions... I found this info on valves, apparently Datsun/Nissan 510/240z valves are the right length, stem diameter, and have a 1.715" intake head diameter which I'm hoping will work in a 300 head without replacing the seat. Any Idea on where to find Datsun 510/240z valves? I've searched and can't find any info or even price on them...any ideas, websites, suggestions? Here's the link http://www.v8buick.com/showthread.php?t=121528&page=2 post #32

May be it can help you for valve option. In Uk a compagny called REC produces racing valves for RV8 :

REC 315 V8 3500cc 1.630"/41.4mm Inlet Std. Stem, Std. Groove
REC 460 V8 3500cc 1.692"/43.0mm Inlet Std. Stem, Std. Groove
REC 477 V8 3500cc 1.692"/43.0mm Inlet 5/16" Stem, Triple Groove
REC 477/1 V8 3500cc 1.692"/43.0mm Inlet 5/16" Stem, Special Groove
REC 508 V8 3500cc 1.750"/44.4mm Inlet 5/16" stem, Ford Pinto Groove
REC 456 V8 3500cc 1.844"/46.8mm Inlet 5/16" stem, Ford Pinto Groove
REC 117 V8 1.350"/34.3mm Exhaust
REC 316 V8 3500cc 1.400"/35.5mm Exhaust Std. Stem, Std. Groove
REC 461 V8 3500cc 1.455"/37.0mm Exhaust Std. Stem, Std. Groove
REC 478 V8 3500cc 1.455"/37.0mm Exhaust 5/16" Stem, Triple Groove
REC 478/1 V8 3500cc 1.455"/37.0mm Exhaust 5/16" Stem, Special Groove
REC 509 V8 3500cc 1.470"/37.3mm Exhaust 5/16" Stem, Ford Pinto Groove
REC 457 V8 3500cc 1.556"/39.5mm Exhaust 5/16" Stem, Ford Pinto Groove

The major advantage of REC valves, they are available with 5/16" and are very light.

I have 477 and 478 in my Tuscan Race Heads.

What modifications did you need to do to make these valves work? That is did you need to shim rocker stands, use different length springs, or any other mods that stray from the stock specs?

Just thought I would add my $.02 here from my build.

4.0l rover ($125)
Crank offset ground to 1.89 journals ($300)
Nissan VG30 rods, 6.070 length, and the kicker, they are the perfect width.($200 for 12 stock used rods, + $ for reconditioning and arp bolts, or $700 for aftermarket h-beams)
Custom Ross forged pistons ($450)

Rover 4.0L heads ported to a minimum CSA of 1.5"
Isuzu 2.8v6 (Chevy 2.8) valves, 1.718 intake, 1.424 exhaust, 11/32 stem, 4.707 length ($80)

Haven't worked out cam and spring solutions, but I am going with bigger seats @ 88% of the valve diameter.

I'm sure you'll be most interested in my valve and rod choices, but feel free to comment on any of it, or question what I left out.

"Custom Ross forged pistons ($450) "
What are the specs on these and are they really custom for $450? I emailed diamond and they gave me an estimate of over $1k

Don't have the specs on them yet, still need to true up the block and heads, so depending on how much is decked off those we can decide on the final compression height.  The crown is going to keep the stock dish, more or less, to keep compression down to about 10.5-11:1, and compression height should be in the 1.1-1.15 range depending on final deck height.  Not going to be much good for nitrous or forced induction.  It will keep weight low and make balancing the crank cheap, mallory can get expensive.

$450 may be low, but my machinist is a Ross dealer and he is probably just cutting me a deal.  He originally told me $450-$600 before I had him doing the valve job on the heads, machining the block, and offset grinding the crank.

Need to make a few additions and edits.

The Nissan rod journal is 1.967" (50mm), not 1.89" like Honda.  The big end width is .8170", just for reference.  I also found eagle H-beam rods for $460 for 6, then $80 each for the remaining 2.

Unfortunately when my machinist got a quote on the pistons, all the guy heard was Miata, and quoted on a set of 4.  The complete set I just ordered set me back $725.  Still not too bad, but I will be going with the stock VG30 rods now, can't spend another $620 for Eagle rods.

Also, I couldn't find a good deal on a 4.6l crank, so I will be offset grinding the 4.0l crank I already have to roughly a 3" stroke.  This obviously frees up another .3-.4" of compression height to build a stout piston.  Maybe it will be able to see some juice one day.