I have searched this question and had no luck finding info on it. So iv been told that if i want to cam/ heads my lt1 to 380-400rwhp i need to replace the fuel injection system to a fasst-ez system or something like that. If someone please can let me know if this is true that would be great and if so why is this required?? Thanks

 

Stock PCM can easilly be tuned for normally aspirated HP in that range. You don't need an aftermarket fuel injection system.

You will need larger injectors, 36 #/hr will be more than adequate. I'd upgrade to a 255 LPH fuel pump.