Level the head on a work bench and fill #2 and #4 combustion chambers with a soap/water mix and blow compressed air into the intake and exhaust ports. Seal the air gun up best you can with a shop towel. It will find the smallest leak at any of the seats.
To have ZERO compression my guess is that you have a big leak at a couple of the valves, bent, sticking, stuck?
That little pit/hole would still seal things up enough to show something on the compression tester gauge............
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73 Ventura, SOLD 455, 3740lbs, 11.30's at 120mph, 1977 Pontiac Q-jet, HO intake, HEI, 10" converter, 3.42 gears, DOT's, 7.20's at 96mph and still WAY under the roll bar rule. Best ET to date 7.18 at 97MPH (1/8th mile),
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