454 into 1976 K20 tips?

[mar-tay1]

 I picked up a couple of trucks lately to build the 4 x 4 I've always wanted. First off I'm in California so I have a 1973 C-10 cab (no smog), a 1976 K-20 pickup, and a 1990 Suburban r 2500 with a 454 /THM400. So I have ; 14 bolt, NP205 and, D44 front. I have the stuff for a high steer/crossover setup. Stuff for a 52" front leaf setup, shackle flip etc etc.
 So the question at hand is, when I yank the small block/thm 350 to install the 454 / thm400, other than the different output shaft for the trans and the exhaust, what else am I forgetting? Mounts? I was thinking about trying out the TBI from the 91 in the truck over the carb, what you guys think of that? Thanks for your input!

[Engineer]

Use the mounts, fan shroud, radiator, etc from the '90 Suburban.

The NP205 that fits the TH400 has a different input bearing than does the NP205 for the TH350 or the SM465.