1986 IROC with ZZ4 350

[ZEDRATED]

So I am starting a new thread, I replaced my Accel 30lb injectors with a set of Bosch3's 24lb injectors and what I am finding is that when the car goes into closed loop it get's really lean. 17-19:1.
It was doing the same thing with the 30lb injectors. I checked continuity from the O2 sensor connector to the computer and it was ok and I just replaced my 1 year old NGK O2 sensor with a Delco one and yet the same thing. I got all the little exhuast leaks fixed up as well, I made a copper gasket at work and used some aircraft grade gasket material. Worked like a charm:
Do you guys think the 24lb injectors are big enough for my set up?
350 ZZ4 with GM hot cam and TPIS miniram.
Any ideas why the O2 sensor is making it go lean???