OK, just cut to the chase and run a "dry" compression test, followed by a couple of tablespoons of motor oil in each cylinder and a "wet" test. There's no need to get anal about an engine that turns freely. These things are as rugged as a Belgian plow horse. I'd suggest pulling the valve cover, not the oil pan, and liberally oiling the valve stems with something like KROIL, PB Blaster, or some other penetrating oil. Definitely DO NOT use stale gasoline from a dirty gas tank to start the engine- - - -the gummy residue it contains goes right to the intake valve stems, makes them seize up, and bends valves and/or pushrods after a few minutes of running. That usually happens after one warmup-cool down cycle when the crud hardens in the valve guides.
Jerry
