What is your budget on the truck? A sure way to rest the left leg is to go automatic and old cast iron Powerglides that mate up to a Stovebolt are not hard to find. The rear engine mount on the bell housing would have to be tweaked. A 1T should have an open driveshaft at the rear end so no problem there or a 54 Hydramatic is set up for a torque tube back to the hanger bearing. Lots of options from budget to bust the bank.
