my car is going to be a heads/cam/nitrous car with some other stuff... I have pretty much everything for the car. Am I going to need a adjustable fuel pressure regulator to bump up the fuel pressure. Is there a way to get the stock FPR to allow for more fuel pressure?

I will be running a walbro 255 pump, and 42# hr SVO injectors.

 

y do you want more fuel pressure? 42# inj. is pretty big, a tune should do all you need

 

If your ECM is tuned correctly for the 42# injectors, you should not need an AFPR. Leave the fuel pressure at stock, and tune in the ECM/chip, not with the fuel pressure. Running nitrous won't affect injector size if its a wet kit, and even with a dry kit, may not affect injector size, depending on how you get the injectors to flow the extra fuel for the nitrous. The 42's will support over 600 flywheel NA HP.