Very strange compression test results

1964 273 engine. I bought the car knowing the engine didn't run right (price adjustment). I know for sure I have to remove from car and take it apart to figure this one out!
Condition:
1) Engine has been rebuilt probably once in lifetime
2) It does run (poorly). Starts right up with no fuss. No idle, but will run off idle. Very rough running, like a misfire but not.
3) No smoke (blue or white) from tailpipes.
4) No oil in water
5) No water in oil
6) No external engine leaks or signs of trouble
7) Excellent oil pressure
8) No odd internal engine noises
9) All valves appear to be operating normally, full stroke, not stuck. Springs look ok.
10) Push rods look straight

Here is the comp test results:
The low and zero results were rechecked numerous times with two gauges.

273 compr test1.jpg