86 caprice emissions?

my buddy just bought a 86 chevy caprice 4 $400.00 CLEAN body & int. 79000 on it. but all the emissions equ. under the hood is missing or crimped off at exhaust manifolds.. it smokes when started (black smoke) and runs like trash of course .. at higher rpms it clears up alot.. is there a in expensive way of getting it to run any better? thank you

Try a bottle of Sea Foam. I've heard it works wonders. You might have carbon build-up from what I gather.

i will try it thanks