Vibration on acceleration??

[87 STEPPER]

Dave it sounds like the converter or the flex plate threw a weight they both have balance weights spot welded to them and i'v seen them go by by on both.....not at the same time and not on the same vehicle but it happens.

If you look at them you can usually tell if one of them has departed from it's spot plus if you see the weight then you can eliminate that being the prob.

Good luck.