Hi HT32BSX115, I installed a 453 Detroit and a Allison in a 47 1.5 ton ford truck it is a very tight fit, also changed the rear axel to a IH load star 1500 it had a five lug bolt patern. I would think about going with a two speed axle the more gears the more options you have when pulling a heavy load. I am not sure but I think your truck has a six lug patern if so ford made them for years . newer trucks should also have bigger brakes that you will need if you go faster than the truck was designed. good luck on your swap and KEEP ON TRUCKING!