you bought the wrong truck for what you want.. the 454 of that era is a giant turd with a tiny cam and low compression. it should however have a 4bbl manifold but use a TBI adapter for the TBI.. the TBI will not support a decent cam. you need diffrent heads, diffrent cam, a quadrajet would bolt right on and that is your best bet for induction. but by the time you do all that, it still isn't going to be much.. you will be farther ahead with a 350 powered 3/4 ton, Vortech heads, 4bbl carb, headders. it will be a stronger runner than the big block