Thread: 454 stock car engine build. Open or closed?

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Hi guys, new guy here. I’ve built a few sbc but never tackled a BBC. I’m building a 454 for a stock car dirt track car. Its really amateur racing. Anyways its 8 cylinder stock engine class. The motor has to have all oem exterior parts on the engine and pass 2 tests, a compression and vacuum test. For compression its max 180 psi. I have a 454 motorhome engine that I already sold the peanut port heads off. I picked up a high rise oval port cast intake and want to use the stock pistons. They have like a 1 1/2” dish. What heads would be the best for my combo? I had like 140 psi with the peanut ports. I want good flow but good compression. Open or closed?

Originally Posted by BBCharly

Hi guys, new guy here. I’ve built a few sbc but never tackled a BBC. I’m building a 454 for a stock car dirt track car. Its really amateur racing. Anyways its 8 cylinder stock engine class. The motor has to have all oem exterior parts on the engine and pass 2 tests, a compression and vacuum test. For compression its max 180 psi. I have a 454 motorhome engine that I already sold the peanut port heads off. I picked up a high rise oval port cast intake and want to use the stock pistons. They have like a 1 1/2” dish. What heads would be the best for my combo? I had like 140 psi with the peanut ports. I want good flow but good compression. Open or closed?

What would I do? Regardless of open or closed, I'd look for the smallest combustion chambers I could find to raise static compression ratio if I didn't want to change pistons.

3856206....65-66...oval..CLOSED..396, 97cc chamber

3872702....65-66...oval..CLOSED..396, 427, 98cc chamber

3904390....67......oval..CLOSED..396, 427, 98cc chamber

3909802....67......oval..CLOSED..396, 427, 101cc chamber

3917215....67-68...oval..CLOSED..396, 427, 101cc chamber

The 702's and 390's are probably the best flowing out of the bunch. If you can afford it, change valve sizes to 2.25"/1.88" on the 390 heads or 2.19"/1.88" on the 702's, although it would probably be about the same money to install some decent pistons and make the same horsepower with more static compression ratio as you could with larger valves.

The cranking compression will be dependent on the static compression ratio and the closing point of the intake valve. It's a complicated balancing act and I suspect that the front runners have spent plenty of dough to find the consistent 180 psi cranking compression and the correct vacuum reading (which you did not list).
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Thanks techinspector1! Like I said its really amateur racing. I’ve been winning races with a 20 year old 350 thats now down to 110 psi. I was leaning toward closed but was always hearing that 781 and 049 were the dream heads. Im on a poor mans bugdet so changing pistons is out of the question. Im looking for completely rebuilt or recently rebuilt heads. What about the 063? I saw a pair of those for sale. Thanks

Copied from www.chevelles.com.......

"The following heads are all cast/based on the same platform, the 063's, 206's, 215's, 219's, 280's, 290's, 702's, and 802's. These were all shown as 97cc's from Chevy, probably by NHRA also."
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For the vacuum its basically around stock engine vacuum. I’ve pretty much picked the cam a while ago. Its from the company who makes performance cams that produce good vacuum. Lift is .515/.530 and its for 1000-5500 rpm. That 60’s high rise intake and some good oval ports should really wake up that old motorhome engine. You can still see the crosshatch pattern in the cylinders. New oil pump, bearings and piston rings would be a good investement. Gotta switch out the oil pan too, I dropped it in a car and the pan didnt clear the frame. Are exhaust manifolds worth changing or it wont make much difference?