please, help fustrated.. going in saine

so ive been working on a 2001 Jimmy 4x4 2 door for the past little while,
Just put in a new motor as the old one was caffed.
Got the darn thing running, with a little miss to it,
A day later the fuel pump went so we replaced it, thinking that was the missing problem, got the fuel pump into her, and changed the distributor and now she is acting like its got a dead cycliner, running ruff and the conpression is good in all six, timing is right on, fuel presser is good, new plugs wires and cap, it ideals at 550 rpm, lack of power, and puffs a little black smoke when you reeve it up a little bit.. acting like its only running on 5
Anyone have any ideas????

did you change plugs, wires, cap and rotor too?

what were your exact fuel pressure and compression readings?

any check engine light / codes?

got runing good now it was a bad valvee

Glad you got it running. How did you have good compression with a bad valve?