how would the car act if the fuel pressure was to high or to low? would it cause the car to have a hard start and then run for acouple mins then die? what should be the correct fuel pressure for a 94 z28 with 42lb injectors and a 255 walbro fuel pump?

 

41-47psi if the stock regulator.
This may be overly simple but you did have the pcm reprogrammed for those injectors and whatever engine combo required them right?

 

yes madz28 set up the fuel constant on the injectors - he thinks i should be using smaller ones then the 42lb - but everyone online claimed with a blower pushing 8-10psi i needed the 42lbs?

 

The correct fuel pressure would be whatever you told madz28 you were running your system at. He can't set the injector constant without knowing the pressure you're running. If you didn't tell him anything, he would have to assume you are running the stock pressure, which is 43.5psi, without the vacuum compensation.