91' c1500 350 / Swap 454
3 Answers
Your best bet for a how to is on a Chevy truck forum that has a performance section. This seems like it would be a common enough swap for the hot rod crowd. They'll have the knowledge regarding how involved project is (swapping out engine cradle, suspension/brakes, tranny, etc.)
You can do this swap with all factory parts since the 454 was an optional engine for your truck.