318 Poly Vibration

jas0162 said
The earlier converter (yours) has a smaller diameter snout than later engines..... I think 66 or 67 and after. You can “bolt together just fine” the smaller size into the later crank with the bigger hole, then the flex plate bolts are the only thing centering the converter to the crank and in a short time you will have problems. You can check this by unbolting the flex plate from the converter- if you can wiggle the converter around off of center when it is up against the crank then you have a problem there. I’m just throwing out ideas here. I really didn’t see any bad vibration problems in your videos.

Just trying to remember, here. Been a long time since I worked on a "poly". If I remember correctly, the poly engines only had the big trans (727 style), with the big converter pocket in the end of the crank. So I don't think it is possible to wind up with a converter/engine mismatch, as I don't think there is a 904 bell that can bolt up to the poly engine.
The problem with converter/engine match ups occurs between 1967 down and 1968 up with the "LA" small blocks , and slant six engines. Not with the "A" (poly) series engines.