[peterhodges1222]

I have a 63 Galaxie 500 xl, 390 fe, Carter electric fuel pump, new inline filter, to a new holly FPR, new Summit 600 cfm carb I start the car pressure is at 8 it runs for 2 minutes pressure drops to 4, I know the gauges are not reliable but the fuel level drops in the sight glass so I know the pressure is in fact dropping. Removed inlet line from FPR, engaged fuel pump and plenty of pressure. Took FPR apart check for dirt, stuck spring, ruptured diafram, no problem. Considering going back to mechanical pump but don't no if I will encounter the same problem?
Any thoughts ?

Thanks Pete

 

[m in sc]

check pickup tube in tank. or for air leaks. if you're sucking air, pressure will drop.

I have a mechanical holley pump, same carb as you, and its at 8-9 psi and drops a bit (6-7) when warmed up.

 

[peterhodges1222]

Thanks m, its something to look at btw I'm also in SC...