Thread: I can't decide what engine to build....need advice

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Attaboy Jerry, pull out all the stops and go big or go home, huh?

35chevy, the 400 2-bolt block has better integrity in the crankcase than the 400 4-bolt. Once you start putting some horsepower into the 4-bolt, the webbing pulls out of the block and you run over the crank. Start your build with the 509 block would be my suggestion. In my opinion, the 400 has gotten an undeserved bad rap for overheating. I'm thinkin' that this crap was started by some dunderhead who bolted 350 heads onto his 400 without drillin' 'em for steam holes and the motor spit out the head gaskets due to localized hot spots at the edge of the bore. Either that or it rattled like a can full of marbles from detonation for the same reason. They'll cool as well as any other SBC if you pay attention to detail and it sounds like you are on that page. The late, great Smokey Yunick said that the thin limit on cylinder walls is about 0.135". Under that thickness, the skidding of the rings on the walls transfers vibes to the water jacket side of the cylinder and separates air bubbles from the cooling water. These air bubbles cling to the water jacket wall, preventing cooling water from getting to the wall to carry away heat and you have a problem. Over 0.135", there is enough mass in the walls to quell the vibes and prevent this problem. Smokey used to cut blocks apart, install glass windows and run the motor so that he could observe what was going on inside, so I pretty much take anything he has written as gospel. And yes, he said the rings SKID up and down the bore, they don't glide smoothly like you might think.

Here are the instructions for drilling steam holes in your SII heads....
http://www.gregsengine.com/350to400.htm

And a cooling system checklist that you may find helpful....
http://www.crankshaftcoalition.com/w...cooling_system

If you'll post the converter and rear gear you're going to use, I'll run up a DynoSim dyno pull for the 400 with SII heads and help you with component selection. Also, the kind of cam you want to run, solid flat tappet, hydraulic flat tappet, solid roller or hydraulic roller. Also, please tell me whether you want a choppy idle, some rump-rump or dead smooth. By the way, another item that has gotten an undeserved bad rap is solid flat tappet cams. You do not have to adjust valves every week like some throttleheads might have you believe. I suspect that twice an year would be a Lord's plenty and you would probably find 'em measuring the same after the cam gets settled in. Personally, I just LUUUUUUV the sound of solids ticking.