One thing I would look into before contemplating this swap would be your locl emission laws. If for example, you swap in an older motor, you will need to possible keep the emission controls of the newer truck, including cats and all the good stuff. If you decide to swap in the FE, take the mounts and stands off a 76/77 that was equiped with the FE and start moving over parts. This will surely require some fab work, but anything is possible with a torch and welder
--Mike