Just thinking on how to troubleshoot… “If the cam is ground for a 351C or 289…”
it would seem to me, you could just manually turn the engine over, and watch the valves.
At TDC for each cylinder (which you could monitor via distributor position) both the intake and exhaust will be closed (valves all the way up).
351C’s firing order is 1-3-7-2-6-5-4-8
Ford 289 engine is 1-5-4-2-6-3-7-8
You might not notice this if you were doing your compression checks just based on spring position.
Anyway, the difference ought to show up within about a rotation or two of the crankshaft. Seems like a pretty easy check that you may have already completed.
It certainly would be good to confirm before camshaft removal.
Good luck
Rocky