P220 Restoration

Were the timing gears off? It doesn't say that in your posts,,

Have you read this section? page 8-2, it does show a way of checking roughly if you're motor is close to the timing points?
Although, it is preset, you can check to see if you're in the range where it should be,, check this out and see if it's close.
You didn't replace the cam shaft or crankshaft? Just had the gears off? Any pictures of the gear positions during assembly?

To test for continuity, you shouldn't have to pull the engine for that.
From one of your posts, you mention talking with Boomer, I take it that was a phone conversation? Have you asked him for his thoughts? He's really the guru on these motors,,

Great, now you can move forward with your motor. I suspect, that's been known to happen before,, the important part is you got it figured out without too much disassembly, (hopefully)