I think that the 454SS trucks were TBI.

 

The early ss trucks had TBI then in 96 chevy redesigned all their engines. Yep thats a 454. I'm pretty sure those trucks had MPFI. I can see it's got intake and it looks like a new MAF sensor. Does it have headers? get some then heads, cam and spray, s/c, turbo.

 

You can tune with Tuner-cat and also Jet Performance has a new tuning software out, but I don't have any info on it. Call up Nelson Performance if you want a tuned ECM. I believe he can tune these year models. Exhaust and tuning is where I would start. A 100hp shot of nitrous would get it moving after that.