I have a blown carbed 454 using the stock fuel pump and also an electric holley (helper) pump. I dont have a regulator at the carb. My dash mounted pressure guage has always read about 8 lbs. or press. Now all the sudden it is climbing as i push the throttle. Goes up to 15 lbs. Could the diaphram in the stock pump be going and creating the extra pressure??? Or do you think i may have a short somewhere in the wiring to the gauge?? The motor still runs fine and is not giving me any fuel related problems.

I have a spare stock pump that i was thinking of putting on to try, but i thought i would ask here before wasting my time.

Is your feeder pump on a regulator? You may want to test the presure at the carb with a mech. fuel gauge.

Feeder pump is not on a regulator. Maybe i should pull the fuse on the feeder pump and see what happens? at least the will narrow it down to the stock pump or wiring.

Didn't notice the first time you had a blower. My procharger motor was set up to increase fuel presure as boost went up.

This is a B&M 174 blower. Fuel press only went up maybe one pound as the throttle increased. I never saw past 8 - 9 on the gauge until now.

You'll blow the floats off the seats at 12psi and it will run all blubbery. If shes running normally, then I suspect you have a problem with your pressure sender or pressure gauge or in the wiring or ground to them.

Well , the electric feeder pump doesn't know about rpm ,it just pumps. The mechanical pump should be rpm sensitive. Is your regualtor before or after the mech. pump?
I used Carter pumps with internal regulators and run 8 to 9 lbs on the dash guages.
Perhaps a bad regulator
If you can make it do it just by hitting the throttle(sitting still) try a mechanical pres. guage at the carb. That should varify the accuracy of your dash guage.

I dont have a regulator. The pressure never exceeded 8 - 9 pounds, so we never put one on. The carb is a Nickerson Holley 750. I will put a manual gauge on this weekend a test it.

My suggestion would be to put a mechanical guage where your sender is to check it first.

Then get into the fuel pump swap and what have you, if it doesn't jive.

DAVE