over drive transmisson for an early A body.

I learned my lesson on skimping a lock up convertor with my diesel pickemup....Was towing 8500 pounds up one of the passes in Montana. Truck was in od, the convertor went to lock up and could not hold the load. Truck shuttered so bad it blew the gps off the windshield and made the cd player skip. Had my buddy put in a triple disc billet/stainless t/c...locks up hard enough that it makes it feel more like the truck is shifting into another gear. Have pulled 14000 pounds or so with the convertor locked, uphill & according to my programmer I had 0% t/c slippage....