Kevin, with your specs and cam you listed,4 advance,and a 60 cc head, I got 9.94 compression and a 7.67.dcr . Seems like its close enough to work, and you can always use the .040 head gasket if you need to drop compression slightly. I did use the jeep stroker website. So it may vary slightly from other calculators. Personally, I would push alittle more compression, and if needed, Scott Brown can get a .050 head gasket to drop compression a bit more. I believe with the head flow, sp3 intake, your gonna see a higher rpm range then most 350s run. But the rods and pistons are much stronger than stock. A 58 cc head nets about 10.17 scr and a 7.84 Dcr. You could go to E85 also with carb recalibration .
Do they make any gaskets other than .020 and .040 for Buick 350's? A .030 would put me in the perfect range for quench, DCR, and SCR for that cam. Thanks for the link Larry, very helpful
Well that's just my luck! A little better planning on my part (piston compression distance that I had custom made to my spec) I could have avoided having .025 or .047 quench as my options...
Are you sure your heads have 62 CC chambers? If so just use the fel-pro blue .040" head gaskets and dial in the compression ratio by milling your heads. You need new pushrods anyway so that won't save any $$ there not milling them.
I guess that's the only way to do it. I didn't want to take much if any off the heads...but... If my math is correct (.005 per 1cc) Ill have to mill .02 to get to 58cc That will put me at: 9.72SCR 7.50DCR .047 quench
Compressed fel-pros are .042 I still would re- check chamber cc and piston in hole. Like Steve says, never saw 62 cc 350 chambers . Can't believe they ground that much out. Plus you said you figured piston comp height with molnar rods at .011 in hole. Dbl check.
No one has mentioned that the factory sbb cast iron heads have open chambers so quench doesn't even need to be worried about at all. The only thing to worry about would be rod stretch and with the Molnar 4340 forged rods they shouldn't stretch more than .010" at full RPM. So the .020" steel shim gaskets should be fine to dial in your compression if those get you where you want to go?
I run the SP3 with a Wilson 1" tapered spacer under it. Hood has about an additional 1" of clearance, but I'm using a Corvette drop base cleaner bottom. I can throw the orig GS cleaner on for a test fit if you want.
Sorry for the ignorance, but could you explain open chambers a bit more? Does that mean the piston has room past the deck and gasket?
No , pistons can not go farther then gasket. Just means chamber is round and close to the bore size. As where other engine the chamber is smaller and more just big enough for the valves to set in,
Not Buick heads, but the picture illustrates the difference. Top is closed chamber, bottom is open. The 67 and up BBB heads are closed chamber except 75 and 76.
After much deliberation, calculation, and hesitation... I decided to go with the cam TA recommended The shop is doing a clean up cut on the heads. I'm assuming that will take off somewhere between .005 and .010. When that's done the cc's will go down a bit and I'll run some new, more accurate numbers. Some pics of the heads before and after:
