About a computer chip...

I have a 1991 z28 350 tpi motor. It is bored .60 over with a BBK throttle body, ported plenum, flowmaster exhaust with no cat. I was wondering if a performance chip in my car would mess it up or would it help, I was looking at JET chips...

Get a custom dyno tune

the custom tune is better for shear power. i got one of Jet's PCMs for my sixer and it did wonders. if you are lookin to make the car more streetable you might want to think about the Jet chip. at least for me, it made a hell of a difference and didnt hurt the mileage at all. i have heard from some people that when you get into the more serious build ups the chips hurt the performance. dyno is prolly the best way to go...