508 cuin. 4.25" arm/7.100 rod. Closest piston (quench) is 0.038" rest are 0.040, 0.041. Mopar/Eddy head. Flat top pistons w/valve relief.

I live in western PA. I'm at about 1000ft, and probably see 500ft on occasion while driving. My highest CR cylinder is 10.85. My cranking cylinder pressure is 190-ish with my preferred lash setting. Intake valve touches down on the set at a measured 77° abdc. No vacuum advance, and mechanical timing all in about 3000. Initial at 23° total at about 35°. I set it and leave it. 160° thermostat. Some -8 NGK plugs.

The car w/ driver is about 4150 lbs, has 3.23 gear, and tight converter (1900 rpm) and no part throttle kick down.

Its on the edge of detonation using 92 octane. Winter grades of fuel are worse.