Header Interference?
I would grind a tad off of that bell housing just need 1/16 inch cause header and eng/trans move together.
Loosen motor mount k-frame nuts and see if you can nudge the engine toward the passengers side a bit. A shim between motor mount and k-frame can help. Factory k-frame tolerances very sloppy so engine probably not sitting in car in correct location.
I run one of these to limit engine movement, keeps headers from hitting things, and does not add any vibrations:
'66-72 B-Body, '70-74 E-Body, '67+ A-Body Torque Strap
I don't think any dents are going to be needed.