318 Poly Vibration

I found information, mostly on fabo, that supports the post from Charrlie_S.

My understanding is:

1962 the crank changed from an extended 8 bolt crank, that used a cast iron trans, to the modern 6 bolt with an aluminum trans.
1962-66 318 polys came with the same crankshaft register as the 273/318/340 engines.
The exception is the 1964-7 273 crank has a smaller crank register, (and slant 6 engines).

I asked the prior owner of the 318 if he could send a pic or measure the original converter snout, then I could compare to my original crank. If the snout was small and my crank register large, that scenario would give me an answer. Doesn't seem likely.

I'm not sure unbolting the flex plate from the converter to see if it is loose is a good use of time at this point.

I need something concrete to check dammit!

To clarify, I describe the vibration as a frequency, because where it manifests itself reminds me of a tuning fork.
That was what I was trying to demonstrate in a few of the videos.

Lost again.