Vinny was past his prime at super middle. For all practical purposes he was a lightweight who’s best abilities topped out at around jr. Middle. If this fight happened, Lamotta would have been younger, bigger and stronger. Pazienza could move and had a great work rate but a lot of that would have been diminished given the stated parameters.
Good Lord, really? Paz can have a syringe attached to his vein in the ring but he's going to hell against Lamotta. He would wish he was in with Jones, Jr again so it would end relatively early and easily.
Pazienza maybe enjoys a couple of early rounds with his speed advantage, but LaMotta mauls him the rest of the way and likely stops him.