Got Shell 93 Octane and now barely idles 1973 Dart 340

That could be one or more of several things.
OOps nm9 beat me to it,
I will add that the tranny vent is in the bell too, so see if it is wet way up high on the passenger side. If the tranny fluid is too high or if it gets too hot, it will sometimes puke a little fluid out there. Then it may not leak again for weeks or months.
If the fluid is on the TC only then it is probably the pump seal.But it could also be a cracked TC-nose.
If the front gasket leaks(rare), it could be wet anywhere. Occasionally the little seals under the pump retaining bolts will leak.

Knocking the weights off is not a thing to be feared.But MRL is probably the go-to guy on this combo.