OK, I have my '88 Fiero GT with a Cadillac 4500 V8 and a 440T4 4 speed AOD transmission.

When I got it, that V8 was probably making about the same HP as the original V6.

The first efforts at upgrading performance were simple, and went well. I fixed some minor problems it had, removed the 2 barrel
Holley that had been adapted in and replaced it with a 450 CFM 4 barrel. Then I adjusted the shift points and feel. That all definitely woke things up a bit!
I felt like that resulted in about a 40 HP gain to around 175, but now it is time to try and make a bigger jump!

I am shooting for close to 300 HP.
I have ordered a 4.9. I am planning to have some 614 casting (Closed combustion chamber) heads
opened up, ported, polished and get oversized valves installed and later rocker arms (1.6 to 1 ratio rather than 1.5).
I ordered a cam from Delta Camshafts. I already have a modified for higher flow intake manifold, as well as a modern improved design 625 CFM carb.
Oh, and if 300 ponies doesn't run fast enough, I bought a Nitrous Express ML 1000 kit!

I have a 4.9 caddy motor sitting in my donor car waiting on me as well. I have all the allante stuff sitting in the garage ready to swap and I was going to do the delta cam. Keep us posted on how the progress is going with pictures.