Juniorsz28

I have a 94 camaro z28 i have done engine mods. i ported and polished the heads 30 degrees put in a mid cam domed pistons stall 3000-3200 long tube headers flow masters k&n kit, shift kit in trans. i had to change the whole distrubutor to new module and aldo change the timing cahina and kit and some other lil stuff i had it dynoed at @ 420 hp to the rr .this was like last year but now its smoking black and this just started so one thing is that i have not change the fuel injectors or installed a iginton box could does be whats wrong with it or could it be something else?