I have a 68 Camaro with a mild 350. I am running a Holley black electric pump through a Holley pressure regulator to a 750 double pumper. When I start it up cold, the pressure is at 9 psi and as it warms up, it drops gradually to 6 psi. Is this normal? Should the pressure be the same all the time? Should I change to a bypass regulator and run a return to the tank? I am confused. Any help is appreciated.