I think the Stroker 300 to 350 has got a lot of attention lately but not too much documented on the 300. Stock connecting rods for the 300 and 225 V6 are the same with side balance pads. 5.96" long. You can use 11/32" SBC ARP bolts to replace the stock ones but you have to resize the rods. The 75-76 Oddfire 231 V6 uses the modern capscrew rods which are much stronger and the same length. Stock 9 to 1 deep dish pistons are really 8 to 1. 10.25 shallow dish pistons are really 9.25 to 1. The 340P with shallow dish is really 9.5 to 1 and 3.8 bore or .050 over. The 3.0 V6 flat top for 3.8 bore is really 10 to 1 with a cleanup decking of bock and head mill. Oiling mods are the same as the other V6 and V8 engines. 502030 Crower cam for mild build, 50232 ideal for performance and 50233 is what Chris used in his stroker and Mike Moor used in his 300. Chris used Crower camsaver lifters for a 350 Buick and Smith Bros hollow pushrods for pushrod oiling. .125 shim under rocker stands due to longer valves and to plug oil holes in heads. Rocker oil holes have to be checked. Larger valves from a 3.4 Chevy V6 1.72 IN and 1.42 EX with Chevy Z28 springs and guides cut down to .530 for Viton seals. Bronze valve guide liners. The only intake is the stock 64 aluminum 4 barrel. You may be able to mill the 2 barrel to accept a 4 barrel base but you will have to weld up the water jacket inside when you are done. Brian Mcmillan is working with Anthony Laney in Australia to make a Willpower single plane for the 300. You can use spacers and a valley plate to use the 215/Rover Edelbrock Performer and single plane Offy 360.
507FB8E8-ED6B-4C45-B718-4F5C06BEF0B8.jpeg
s-l640.jpg
340p.jpg
300rods.jpg
Picture of capscrew rods:
capscrew.jpg
They are cast Armasteel . Should be magnafluxed. Rod weight of stock 300 rods are around 600 gm Capscrew around 630 gm. They both can be lightened quite a bit by minimizing the balance pads. The capscrew rods in the picture have already been lightened. In the 350 the early rods are good to about 400HP the later capscrew to about 600Hp if prepared properly. Sanding casting flash on outside of beams and any sharp edges. Bead blasted.
You can use small journal SBC aftermarket 6" connecting rods if you machine .050 off each side and both ends. Bore small end out .010. Gain about .3 in compression.
Thanks Jim,
I can't believe this!
I have another block I was going to build into a replacement. I'm looking to go lighter with modern pistons. Do you know of any part numbers that are close enough to work with? I may go with V6 rods. I think TA Performance has a lighter steel flywheel available. I'm still deciding the cam to use. I"ve been running the Crower 502033 for 70,000 miles so far. May just order a new one and lifters.
Mike
Mike, to go with lighter pistons you need longer rods. 350 Buick 6.385" capscrew rods. 6.25" SBC have available 1.58 compression height pistons . 6.4" rods open up 1.33 to 1.44 pistons. All those rods either are large journal SBC (You could use spacer bearings but have to have 3/8" rod bolts) or NASCAR small Honda size journal. There are 6.2 Nascar rods that Jim B is useing in his stroker but you would need custom pistons. I couldn't find any off the shelf. With the open chamber 300 heads you don't have very much quench but if you used the later Rover or TA heads with small chamber you would want to zero deck to take advantage of that. Decking the block and /or milling the heads to get around 10 to one is what you want with aluminum heads.
https://www.ebay.com/itm/203041144782?epid=11027602753&_trkparms=ispr%3D1&hash=item2f4631ffce:g:1iIAAOSwh0xh0l6u&amdata=enc%3AAQAGAAACsPYe5NmHp%252B2JMhMi7yxGiTJkPrKr5t53CooMSQt2orsSjVt3vLKCbov98Z19qhuwY7LKUl8abxYrRH88u8Kai6BsC3GPUam%252BTVQ7z2Xunvy039ehWlTZNGgK84GHOa2cF6xT8rHjOINzPfDNPSQNe4WqZoTAMQRqDXVEezSQ5UeMmXUgnKFgshvGOH1da1teKyoVCxYT8HWtktKDhYN1%252FsZIoYOytJdMve%252FI3%252B0qAskDdqKDWsS9Hh1iYKZRrqsJ1tqkO6LKW5g6u1wyWq2PD8IEhCc5cHs66oVaScKEQO403l4svMg8hiLCWpyqYgaBXAqo1qgveMSw6n%252FckDOk2ckTpjSNi6b%252BlWEWdUgVDawPRCUvCV5n%252FsBn14no%252BEHn0kJRkrBeQiyDRpR5mk0O0xoU8mI%252Fvy5PQB4a6UpJmJzrjcyb4g2IaNlLSY1D6upvTO6KSKftNZEJfLnRrEatM8i2D4CTIzR2SUZG7N%252BuXVIwh9Y2V9kJ3KmBgjcoA5nS5uX2Wfat%252BcchypkMTbOOrO%252BDmJarNDuw9WDgTjQ8wc40lTfzsQkQyXdYc9mpiI3XvcZNnfuWKaq2HA87oXvOvaE7%252BKaJw7g9KACELUCcXWYTezdVUb5ejv2wZpXC5whpYGxMCRNqpGPAVXeqir8u5VAde3%252BYK%252BUJaWhnpiR5d%252Bam7ofyjXdG2aoQjOTnSSLZ7uN%252BNmpXEnb1VZqz%252B4BaJV8KFrhRWuh1U1WFmUXoIFyxV3UnRRIBRWNMLa6qaVwBdShsViYEyVmPeENfaTDsN5y64RKb7Fob9M0cODeCvmHqEGITFklBAW2Gvu9RxL8xAmMf45qeavBP5wStS7E5Umo8qz0Af9XpIgTdPZsULjUgVhwNkqIt5lf637STCAWd4da1pZycPIozXeT8LDzSWzE%253D%7Cclp%3A2334524%7Ctkp%3ABFBM6sSa49Nf
Mike, This 3.78", 1.478 compression height, .030 over for the 300. Piston from a 3.5 Chrysler V6 would be perfect if you have middle raised portion milled down. Edit: .020 off top including raised portion. That is with the 350 capscrew rod.
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For those that want to use the NASCAR 6.2 rod with the rover or TA heads I've found the perfect piston. 4.2 Jeep.1.633 compression height. You would cut off the tabs extending down from the skirt.
s-l160037.jpg
Those rods with oversized big end bearings aren't going to clear the block and the cam so I'm pretty sure those are out.Here are a couple of shots of the Wiseco pistons. Cost me $1140 a set which these days is a good deal.
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Next is a shot of the Wiseco wrist pin beside the stock SBB one. That saves about 100 grans.
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Last a shot of the Carillo Nascar rods that I paid ~$100 for/set. The saved money goes into the pistons. I recommend the Pankl rods if you can get them. This is for the 350 crank setup.
Jim
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Here is the label from the Wiseco pistons. Note these are for zero deck, 10.5 CR with 350 crank and 6.2" nascar rods using the TA or 4.6 Rover heads. You might be able to use them with the stock crank and 350 rods.
Jim
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Hello everyone. I've been stalking this forum for a long time, but now have some questions. I am beginning an MGB-GT Sebring project and have been working on accumulating components. I have a Buick 300-4 (aluminum heads and intake) that I intend to build for this project. I have learned much about Nascar rods recently and bought a set of low mileage 6.320" rods recently ($100.00). So now, I am looking at pistons. I have come across three candidates: Jeep 232ci (3.8) pistons which are 3.75" bore and CH of 1.581, AMC 304 pistons with 3.75" bore and CH of 1.581 (different pistons than the Jeep), Chevy 305 pistons--3.756 in .020 overbore and CH of 1.540. Since all of these have a greater than the stock height of 7.819 to varying degrees, I assume I could mill some off the piston tops--taking into consideration that if I use a composite head gasket, I will add about .020" (meaning a bit less to mill off). The Chevy option seems the best, but I'd be interested in getting feedback from folks here on what I'm doing. TIA.
Jeep232Piston.png
AMC304Piston.jpg
Chevy305piston.jpg
Check your wrist pin diameters to be sure you can get a match. Without bushing the pistons if possible.
Jim
As an aside, for those who are looking at Nascar 6.2 rods (which are much more common and generally pretty cheap), I found these 3.75" bore pistons from the 1967 Buick 225 V6 which look very promising: 6.20" rods + 1.835 CH is 0.216" greater than stock. Add in a composite head gasket and you have a combination that could be interesting.
What size pin hole in rod? Diamond piston compression calculator is your friend.
https://diamondracing.net/p-10-compression-calculator.html
Piston catalog to compare pin height and diameter. Look in 3.736, 3.75, 3.78 and 3.8 bore sizes.
https://uempistons.com/c-29-silv-o-lite.html
I used to almost have that catalog memorized looking for a good piston & rod combo for the Rover 3.9. :)
When you pull up a piston list, click on "BORE INCH" in the header. It will relist them by bore size.
Thanks for the feedback. That catalog is gold--I know what I'll be poring over tonight :) Just for my knowledge, is there a reason I wouldn't want to bush the pistons? Or, on the other hand, bore out the rod pin hole a small amount?
I've searched the web looking for bushed pistons. There were a few VW and Diesel that used bronze bushings but were rather complicated with a step and circlip to hold them in. I looked up expansion with heat and aluminum expands twice as much as steel and bronze falls in the middle. There was a discussion with machinists that using aluminum tubing interference fit would be the best but I'd still stake both sides for insurance. You may have enough metal in the small end to bore for the press fit pin. If the rod has a bushing you will be able to bore out that much but is it enough. Some of the Pankl NASCAR rods have small .7 something holes some are .8 something which would be better. The build Chris did used a steel bushing for press fit pin and has been running fine the last 8 years.
Eric, Does your NASCAR rods have SBC 2.0 journal size with 7/16" rod bolts? The extra width over the 3/8" may cause clearance issues. Also compare the Buick rods with the NASCAR ones for thickness at the big end and small end.
Jim, forgot to answer the question about the piston rod. The rods I got are .912 on the small end. My original thought was to bore them out slightly, if necessary (rather than bushing the pistons)--although by looking through that catalog, perhaps I might find a perfect fit.
Nascar6.320rods.jpg
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. You forgot big end size, 7/16" bolts?
Two sets of these would be a good deal. You could use the 305 Chevy ones if you mill .025 off, but you would have to bore the pin end to .924 for the Chevy .927 pin.
https://www.ebay.com/itm/304275241675?_trkparms=amclksrc%3DITM%26aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Dbcbcdc1865404481b33d14047883dd9d%26pid%3D100675%26rk%3D1%26rkt%3D15%26sd%3D304275241675%26itm%3D304275241675%26pmt%3D1%26noa%3D1%26pg%3D2380057%26brand%3DEnginetech&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3Ad1d75533-846b-11ec-88a4-660e69bc897c%7Cparentrq%3Abc417e0317e0ab96ed0995fbffef408a%7Ciid%3A1
Thanks again, Jim. Great information. Yes, they are Ford sized, apparently--this is the description from the bay: "SBF SBC 2.00 X 6.320 Carrillo Rods. Nice used set of Carrillo rods from roush racing. Big end is 2.000 with bearning. Takes a .912 pin 6.320 center to center. .902 big end width . Magged good. They have the 7/16 carr bolts." I will definitely check out the 2.3 Turbo pistons. Thanks.
Jim, yes 7/16" bolts. I guess I'll have to compare them to the Buick rods, as you suggest, to make sure there are no clearance issues. I'm only $100 into them, but they look like great rods (if I can make them work).
Clearance I'm talking about is rotating inside the block. Stock rods have very little room by cam and inside of block. Some have ground the rods to clear the cam and the block for clearance. The thickness of the big end has to be the same or less for side clearance rod to rod. Those rods should take stock SBC small journal bearings. On Chris's build the front two rods hit the shallow part of the pan and the last two hit the windage tray. Ball peen hammer on the pan and washers to space the windage tray down.
All good advice--it'll be interesting to see how things work out. Great insight from all of you, as I thought. The 2.3 Turbo pistons look very promising (and super cheap at $14 each).
Ford2.3TurboPiston.jpg
Check the front rod bolt heads against the suction galley casting and the shoulders against the rear cam lobes. .050" clearance is good if you can get it. May have to shave one or two shoulders and recess one or two capscrews.
Jim
Thanks Jim, good advice.
I'm getting to tear down my 300. Can anyone suggest a good book (or perhaps Youtube) that will guide this--and also a good manual on rebuilding it. I've rebuild engines before, just not this particular engine. Thanks.
It isn't much different except the oiling mods and tighter clearances .Do a search here and on V8Buick for more information.
Jim, thanks for the direction.
I have a crank with 91,.5 mm stroke and have later 5.95" SBC rods (for 2,100" journal). I am using special inserts to suit that rod bore and 2,000" journal. That combination clears the cam but did not rotate inside the block. I think I had to grind clearance at 2 locations. The issue was with the cap head bolts and I think I also machined a small chamfer at the head of the rod bolts. I did not like grinding the block at oil gallery that much.
Thanks Jukka, I assume I will also have to chamfer a few of the bolts, as well.
Can someone look at the UEM piston link tthat was previously posted? I checked yesterday and, unless I'm mistaken, they have eliminated the option of searching by bore size and other criteria--making it mush less useful than a few days ago :(
They have definitely been working on the website. Webmasters seem to think they have to update & modify site just to make them fresh. Doesn't always make them better.
Select a piston brand from Product Lines. Scroll down & use the Filters column on the left to select Bore Diameter. Not quite as handy or useful as it was, though.
Glad they kept the calculators.
Thanks Carl, wanted to be sure I wasn't missing something. What was a five minute search will now take a lot longer. Oh well.
Jukka, Did your rods have 7/16" bolts? That will add to the width over the 3/8".
Yes, 7/16" bolts. But since my rod bid end width had to be a touch over 0.76" it did not matter whether they are 3/8" or 7/16".
The crank is a weird stroker item for TVR500 i.e. 5.0 litre version.
New forged pistons available for the Buick 300 V8:
https://dssracing.com/collections/buick