i just recently replaced the fuel pump with the granatelli 255lph and i got a new fuel pressure regulator and new fuel filter and i had the car running at 45psi and when i turn it on it will run and then when the engine warms up it drops to 10psi and the motor shuts off what could that be cause it only shuts off when the engine gets hot

 

If the fuel pressure suddenly drops 10psi on warm up, its most likely the fuel pump. Have you checked to make sure you have good voltage to the pump?

What brand fuel pressure regulator did you buy?