There are five major engine families of Fords. The small block (260,289,302,351W), The 335 series (351M,351C, 400), The FE series (332,352,360,361,290,391,406,410,427,428), and the 385 series (429,460). The small block has its own bolt pattern, the FE has its own, and the 335 and 385 have a common bolt pattern. The only variation is the 351C, which has the small block pattern. You can use the 390 engine, you will have to get creative with the motor mounts, exhaust, radiator plumbing, wireing, etc. Nothing to major. You will need the rear sump oil pan, or the front end will self clearance the first good bump you hit. You will need the bellhousing from an FE, and the best transmission t-case combo would be from a 78-79 truck with the married unit. The 70's model 1/2 tons all had married trans, but the 3/4 tons had divorced until 77. 76 was the last year for the FE in trucks, and 72 was the last year in cars. IMO the FE was one of the best engines Ford ever made. They made great torque, but the heads really limited them in the horsepower dept. Edelbrock makes a set of aluminun heads that can really make some power. They also make an aluminum intake. As far as I know, these are the only aftermarket heads and intake for the FE. I have done this swap into an 83 myself, and it worked great. If your not to mechanically inclined, then I would suggest going with an engine that Ford put into that body, because you can find all the parts to make it a bolt in swap. These bodies 80-86 came with the 351M, 400, or the 460. These were the only v-8's Ford put in these trucks. IMO the 351M-400 make good boat anchors, but very little aftermarket support, and very hard to get much performance out of. The 460 is the best bet. Hope this helps.
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