i have a 96' z28 with a cold air, and slp exhaust.
if i put 30lb injectors on would i gain horsepower, or would that just be too much fuel into the engine?

 

Stock injectors are all you need. When you go past 350 flywheel HP, go larger. Using a larger injector than you need will not gain you any power. The PCM has to be programmed with the new injector size, and will just reduce the injector pulse widths, so it delivers the eact same amount of fuel your stock injectors were providing.

If you install them without a PCM tune, it will run rich, particularly at wide open throttle.