Engine/drivetrain vibration?

When I built my 360 over ten yrs ago I remember telling the transmission guy, in fact I wrote it down for him to make sure the converter was balanced for a 360 and the nit wit gave me a neurtral balanced one. You will know right off if that's what it is, car will shake like hell, I thought the engine was misfiring. Lucky I didn't drive it much that way, probably at the very least would have damaged the main bearings.

This was after removing the trans and replacing it myself for the second time as the same dope that put the trans together made it so it only had high and reverse. I tried jb welding the correct MP balance weights on to drive it to his shop so he could take it out for the third time instead of me. The weights flung off and cracked the trans case. Spent weeks looking for another HD904 case that would hold the wider band. I orignally farmed it out to save time so I could bolt the engine together and disassemble the car. Won't make that mistake again.

When it's a Mopar you can always count on your farmed out work to add to the excitement. Good times............