We have the Racepump pump and the Racepump regulator installed on our IMCA modified. (355 CI) We are unable to run 9 PSI to our Willys carb due to flooding. We can cut the pressure back to 5-6 PSI @ 4000 RPM and the engine runs good, doesnt stall... The problem is the PSI changes after you go on the track. It grows to 7 or 8 PSI when on the throttle. At idle after a few minutes the pressure decreases to around 3 PSI. Then when you throttle it up to about 5-6K the pressure jumps to from 7psi to 9 psi. We have the regulator installed after the pump, before the fuel log. We have a port in the middle of the fuel log for our gauge pressure. We have the idle bleed installed. We dont have the vacume hose attached to the carb but just open. Any help will be appreciated.  

Thanks Howard. At what PSI should we set the reg at 1500 rpms's? Also on the tracks we race on, we dont get to hot lap, so the only way we could run it fast before we connect the hose to manifold vacume would have to be after a heat race. Should we just connect it after we get the engine up to temp before a heat race?