Need help understanding what was done to my '63 Valiant convertible

That motor in there has spool type mounts. That's why he welded the ears on the k frame. Not familiar what interchanges on a 63 but if a 73-75 a-body K frame fits I would go that route. Better motor mounts. You would need to use that year sway bar and I believe steering parts as well. Get a whole assembly with disc brakes and all. It will give a larger 4.5 bolt pattern though. Or get a 68-72 K frame set up.
Guy's, please correct me if I'm wrong.
Welcome aboard and good luck.
Sorry about your dads passing.