I will switch over next time I try, I guess I don't quite understand, doesn't vacuum drop to 0 when you stomp on the gas on both ported and manifold vac? Didn't hear any pinging but It would have been hard to hear over the exhaust.
I actually clipped the old distributor connections off to check them thoroughly, they were good. Going to solder new ones on and try again.
If I had stray voltage getting through the ground, what would that look like on the meter? Coil hot to distributor case showing less or more than battery voltage? I am really electrical-illiterate.