Buick 300 Stroker - One More Time

[Airwreckc]

Hi all,

Does anyone have any idea the potential for the 300 with the 350 crankshaft using the stock aluminum heads (or really, just a good valve job and mild porting) and standard 4BBL manifold (and whatever is an appropriate carb and camshaft)?  Also, I was looking at the Sniper 2BBL EFI unit and noticed it's supposed to be good for engines of "up to 350HP".  I also have a 2BBL manifold and was wondering if this *might* be a good choice for my engine if I decided to use the standard heads and 350 crank.

Just still considering my options before I pull the trigger on the much more expensive TA heads and possibly Brian's new intake manifold.

Any and all opinions are welcomed.  Thanks.

[mgb260]

Eric, Glad to have you back! Crower 50233 With Brian's intake with 4 barrel Sniper would be killer combo. 2 barrel combo will cost some HP. If you go to the trouble to stroke it don't skimp.

[Airwreckc]

Thanks Jim--and I appreciate your help!  Any idea what his intake will cost?  I'm starting a list of the parts.  Still on the fence about the heads, but I think the TA heads are the ones, unless that intake is better with something else.

[joe_padavano]

This article on building just such a stroker 300 Buford remains one of the best things Hot Rod Magazine has ever published.

https://www.motortrend.com/how-to/hrdp-1103-how-to-hot-rod-any-engine/

[Airwreckc]

Joe, that is definitely a great article.  Would have been interesting to see what they would have gotten with aftermarket heads and/or EFI, but it remains my inspiration for my build.

[BlownMGB-V8]

Don't overlook the stroker thread on MGE and the 300 thread on the V8Buick small block forum. Lots of good info there.

Bear in mind that the stock SBB heads and the TA heads have different chamber volumes so you can't just swap from one to the other. A good compromise is to build the engine with late Rover heads and have the ability to do a direct swap to TA heads later.

If your target redline is under 6000rpm there is no real need to use forged rods and pistons, but for a stroker custom pistons may be necessary to get the desired squish and CR. If you have to use custom pistons you may as well have the ex-nascar forged rods and some peace of mind about over-reving. I've found Wiseco to be a decent choice. There is an absolutely huge difference between the strength of the stock rods and forged ones. The ex-nascar ones run about $100 a set.

Jim

[Airwreckc]

Thanks Jim B,

My plan is to use Nascar forged rods.  I was able to pick up a set for about $100 awhile ago that I believe will work well with the Ford 2.3 Turbo pistons.   IF that is what I would run with, can you help me understand the pros and cons between using the late model (4.6?) Rover heads and the aluminum 300 heads.  Also, from what I can tell from the Dan Jones chart, the SBB heads flow better than the 4.6 Rover heads, but I *think* I remember that those SBB heads were highly ported and maybe the Rover heads were stock (so maybe not apples-to-apples?)?

[mgb260]

300 Buick heads outflow the Rover heads but have a large combustion chamber. The Rover and TA heads have a smaller chamber . So you can use the same pistons if you decide to go with the TA heads later on.

[Airwreckc]

Jim N,

Thanks, that's good to know.   I do like having an upgrade path.  I can't recall the calculations I did when I bought the Nascar rods, but I think at that time, I had the 300 heads in mind.  So now, I have to figure out how the two heads might compare from a CR perspective with those rods and pistons.  Also, I think I recall there being some advantages to the shape of the combustion chamber in one vs the other?

[mgb260]

300 large open chamber can run a flat top piston but not at zero deck. Rover and TA require a dished piston outside of dish at zero deck. Chris's combo is about 10.3 compression. 300 head with flat top. Jim B would know cc of dish required for the smaller chamber.

[Airwreckc]

Thanks Jim.

The rods I got are .912 on the small end (SBF) by 2.00 on the big end X 6.320.  When I was previously mulling this over, you told me:

"That pin is typical Ford size. Look at 3.78 Ford Turbo 2.3. pistons. You need 1.52 pin height for zero deck. Those are 1.578 but have an extra thick crown and would be no problem to mill .060 off. With a true flat top I would grind off the lug in the chamber and figure 58cc for chamber in the calculator. I get .005 down from zero deck and 10.3 compression. You would have to measure to be sure."  

I believe your comment was in reference to using the 300 heads.  Do you agree with that?  If so, I assume IF I wanted to use the Rover heads, I'd need to find a different set of pistons, correct?

[mgb260]

Yep, For the Rover heads you would need a deep dish probably 30 something cc. Rimmer sells the largest valves for the stock Rover heads. Pretty close to the 300 valve size. You could use spacers and valley plate with the Edelbrock performer intake. You wouldn't make the power that the TA heads and Willpower have but have nice throttle response.

[BlownMGB-V8]

Chamber size for the TA and Rover heads is going to be about 31-32 cc. With a zero deck piston having a 35 cc dish you should come out at about 10.5:1 which is a good ratio for a street engine with alloy heads. The TA and Rover heads are more of a closed chamber design and can make use of squish area. Standard Fel-Pro blue gaskets and a zero deck will give you about .040" squish.

A 6.2" rod with the 350 crank and a 1.405 compression height should put the piston at zero deck height, depending if it's been surfaced. So another .120 on the rod length means cutting the compression height down to around1.280" Should be plenty of room to do that with a standard ring package, even with the dish. I had some Venolias made up with a 1.283" CH and 22 cc dishes and they were a thick crown piston for blower duty and had a standard ring package. Still had room between the oil ring and the piston pin but that was with a 3/4" piston pin. You'll be getting a little close there but it should still work. With a custom piston and a thinner ring package it would not be an issue at all. But, you may not find a suitable off the shelf piston.

Jim

[Airwreckc]

Jim and Jim,

Thanks for the insight.  I feel like the light has finally turned on.  Time to do some more research on pistons, which might drive the head decision.  I already have the 300 heads, so I'm leaning in that direction.  But if I'd need custom pistons for the 300 and could find some off the shelf ones for the Rover, that might change things, especially since the Rover heads are so cheap (and would give me an upgrade path or easier replacement in the future).

As always, I appreciate the guidance!

Eric

[mgb260]

Eric, I thought you had 6.2" connecting rods? That is what I calculated. You are close to stock length Buick 350 Rods. Chris used 2.5 Ford SOHC pistons with 1.19 pin height for his build. They have .912 pins. Your rods are 060 shorter than stock 350. I get 1.25 pin height with your rods.

[mgb260]

These pistons look good with the small chamber heads. Block should be sonic checked as these would be .060 over. Pin hole would have to be honed for .912 pins.

https://www.ebay.com/itm/273956947909?hash=item3fc91b47c5:g:RKIAAOSwFttdSLG9&amdata=enc%3AAQAHAAAAoHC%2BfWCSmg1Zt4TsYExiLX8mMTL8F6uGDGqqD370g%2B6Cs0xQen1OTZS8yMv5kAwshAJolwssny4HCIaIMVlY475eVb4krp7FLKYPIQtnpPpojzU0vI7h0OL5aHz5BN8eSWQK5V%2BH0ViZRAKNpHTW7tbUWr8%2FCw1lgwLtCtTzLm8Ny%2FgD8MR1Kbz6E2jHO1VK8X0CKtAM5BaT3mADRkqN6fQ%3D%7Ctkp%3ABk9SR57YjYCRYQ
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[Airwreckc]

Jim,

It's distinctly possible (even likely) I made a mistake when I told you what I had--if so, sorry about that.  So, I just checked and sure enough, I have 6.320 rods.  So, I'm confused about what you mean about 1.25 pin height with my rods--do you mean with the turbo pistons?  Would the 2.5 pistons that Chris used work with the large chamber 300 heads and my rods?  

Thanks for the eBay listing for the dished pistons, you save me a lot of searching if I go with the Rover heads.

[mgb260]

No, it changes everything. 2.3 Turbo pistons are too tall and Chris's pistons are too short. The one above would work.

[Airwreckc]

Got it.  Makes sense.  Thanks again.

[BlownMGB-V8]

Very good price on those pistons. They don't specify the dish volume but it should be close. Deck height on the 300 is 9.543 so run your numbers on those to see where your pistons end up. I show them .044" down in the hole which means you'd have to use the steel shim head gaskets to get any meaningful squish out of them and then it'd be .054" which is a bit more than optimal but a .014" skim of the decks puts you right there. (Not that I'm a big fan of steel shim gaskets) Can't say what the CR would be without the dish volume.

Jim

[MGBV8]

Head combustion chamber size:

Early Rover  36-37cc

Late Rover (10 bolt) 28-29cc

300 Buick (alum.)  53-54cc

These are the most common reported CC sizes.

I have all three in my garage.  Some cold, rainy day I need to cc them.

[BlownMGB-V8]

TA should be 1 to 4 CC larger than late Rover heads according to that and my measurements of the TA chambers

Jim

[mgb260]

Remember those pistons are for a V6 so you have to buy 2 more.

[Airwreckc]

I do like the pistons Jim N. suggested, but I am concerned about the overbore requirement.  So, I want to look a bit more before I decide.  Can anyone tell me the optimal dimension (at or below the deck) for the combination of the rod length and compression height for both the 300 and Rover/TA heads?  I've tried to verify the dimensions but haven't seen exact numbers and I'm not convinced my backing into it calculations are correct.  I saw Jim B. say earlier that with a 6.2" rod and a 1.405" CH, the dimension is at top of deck--what confuses me is that I have in my notes that the standard rods of 5.963" + Buick 300-4  pistons at 1.859" CH  = 7.822".  I'm not sure where I got that from, but perhaps the Buick V8 site (?).  And I think I understand that, at least for the Rover/TA, we'd want to be at top of deck (whatever that number is) and have a dished piston with about 3-7cc of volume in the dish?

I also prefer, as Jim B. mentioned, to use composite gaskets, so I  know that will make a difference.  This decision seems to be driving a lot in my engine and I don't trust that I have it right yet--so I appreciate your patience with my (lack of) knowledge.  Thanks much.  --Eric

[BlownMGB-V8]

Take your deck height: 9.543"
Subtract half of the stroke: 3.850/2= 1.925
Subtract rod length: 6.320

The result is piston height for zero deck. .040" thick gasket gives .040 squish.

Jim