I installed an engine for my fried on his 1995 camaro Z28. The heads have been ported out to 185cc intake and has 2.00" int valves. I am not sure of the exhaust side. It has been bored out to a 355 and compression bumped to 11.5:1. It has a 242 degree cam and 1.6:1 roller rockers. Cam lift is .542, and it has MAC mid length headers with a high flow CAT and SLP cat back.
After I got everything buttoned up and did my initial break in I took it for a ride and found that after about ten minutes of driving it runs like crap, seems like is is loading up on fuel but I still have stock injectors in it because my friend bought Ford motorsports 30lb injectors and the car wouldn't run with them in it. I had to bump the idle to 1000 RPM's so it wouldn't stall all the time. I was hoping it would run to get it to the dyno in order to tune it correctly but I am afraid to have him drive it anywhere. On my scan tool it shows it going rich and I know there is no vacuum leaks anywhere I didn't expect it to run perfect without a tune but I think it should at least run enough to drive it conservatively. I can't imagine why this is doing this the coolant temp reads 88 degrees Celsius and it is in closed loop before the ten minutes. I have no faults in the PCM and none in the transmission. Also the PCM did learn the A/F mixture. I am not that familiar with GM's but I just wanted to help out a friend and get another fast V8 on the road to take care of some Honda's. So where should I go from this point? Should we just tow it to get tuned are the GM computers that sensitive to change to the car would act up this badly from these mods? Is there a way to check the Opti spark for correct installation? What should my advance look like on the scan tool and base timing? Any help is appreciated thanks for your time.

 

Sounds like it needs a tune. Different injectors won't work unless it is tuned for that specific injector. PCM is probably all in a frenzy trying to learn.
When you say you "bumped" the idle I take it you adjusted the throttle blade stop screw? If so, that's not an idle adjustment. It's to keep the blades from gouging the TB bores. When properly adjusted you should only see a hint of daylight through the bores. Adjusting that screw can mess with the parameters of the throttle position sensor.
Make doubly sure you do not have any exhaust leaks.