Headgasket for Kb399 and 302 Heads

If I’m following what you are saying, you can’t measure P/V clearance for maximum valve lift at TDC. The valves are nowhere near max lift at TDC.

Max lift on the intake will be at where ever you degree the cam. For example, if you install the cam on a 106 Intake Lobe Centerline you will be at max lift at 106 degrees After Top Dead Center.

Max lift on the exhaust is After Bottom Dead Center.

Always, ALWAYS degree the cam. Always.