Adapting a torque tube rear axle to a T-5 would require some very creative machining- - - -definitely not a bolt-in swap. You would need to swap the whole rear end, not just the driveshaft. Try to find an axle with approximately the same wheel track width as your original axle, and fabricate spring pads and a driveshaft to couple everything up. There are a few Japanese pickup rear ends (and their American badged clones) such as Mazda, Mitsubishi, Nissan, and Toyota that run the same 6 bolt wheel lug pattern, and would be about the right width for the 46 chassis.
Jerry.
