Headgasket for Kb399 and 302 Heads

72DMag said

Thanks!! I'll reach out to comp cams. I did a similar measurement for them so I could get max lift on a 383 cam I built with old school trw dome pistons.

Predict piston-to-valve clearance before ordering a cam with a valve-drop test

I think I'm good on all other clearances and should be fine with an .039 head gasket. I do see why Keith black states these dome pistons can't be used on magnum heads or closed chamber aluminum heads. I think the 302s are as closed chamber as you can get.

Doing a quick check that puts compression ratio roughly at 11:1.

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I get what you are doing. Valve drop at TDC. But you don’t use max lift because it doesn’t happen there.

You have to know the valve drop at TDC for the cam you are using at the installed intake center line.

If you know what lobes you are using, Comp lists valve opening for all their lobes in the lobe catalog.

If you have those numbers you can drop the valve at TDC and see what you have.

Of course, you will have more clearance than that due to head gasket thickness and lift loss due to rocker arm flex. That’s a whole ‘nother conversation.