Valve to piston clearance ?

greymouser7 said

how much stretch is there in the valve train when it heats up?

When Jim/IQ52 competed in the engine masters Mopar muscle challenge, this other guy with a 361 had his valve hit his 361 piston and blow up the motor. I assume that he did a valve to piston check...? is this limit pushed with these kind of builds?

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The 361. Somebody there just made a big mistake, all eight exhaust valves were hitting the top of the cylinder walls/deck....small bore/big exhaust valve. They said they had checked all the clearances. #2 exhaust valve was the first to break and shut the engine down. You could look into the exhaust port and see the camshaft.

Our 451 engine, two years before, had .052" piston to valve clearance on the intake and .068" clearance on the exhaust. We had no problem spinning it to 7600 rpm, but, I'd like to think that was because we know what we are doing. Its important to be smarter than your cylinder heads.