it came out as a gross polluter, here are the numbers, this is a 90 vette 350 with LO-3 heads and electronics that passed when it was in the donor 89 camaro quite easily.

`HC PPM

15mph max 126 measured 477
25mph max 101 measured 744

CO%

15mph max .79 measured .46
25mph max .59 measured .68

NOppm

15mph max 1097 measured 2327
25mph max 927 measured 1898

car stubles a little, and I know for fact the cat is hollow and its air injection pipe is off .... I personally think with a new cat and good tune up and a o2 sensor and tps adjusted I should be able to squezze by the HC problem.

the CO% and NOppm is what baffles me, the engine passed smog when it was in the donor camaro which was less than 6 months ago so I think we can rule out internal problems.

timing is right on but that all that was done prior to the smog test & the electronics are functioning correctly, so how about some help guys, but lets stay away from pouring alchohol in my tank, I can afford to pay for the parts needed to fix it right so what will be problem areas that need addressing on this engine

 

with no cat on it, your CO numbers look lean, which will cause your HC & NOx to be high. a cat alone probably won't clean up your HC enough to pass, i would get the injectors flushed with the tune-up, the new O2 sensor & new cat with the air injection hooked back up.

on the NOx part, check the EGR system, on a good running stock motor with everything working properly the NOx is normally fine without a cat, if it is out of specs, normally its not out by much.
engine temp also can drive up NOX, make sure your not overheating, a 180 T-stat & fans sets to come on around 190-200 would be good, too cold can drive up CO & HC.