Reply to "Fuel Pressure Varies"

...I bet You the 20 Plus Year Old Mech. Fuel Pump, has a Ruptured Diaphram!! You will also be mixing oil with the fuel and smoking out of the Exhaust AND there would be Gasoline in the Oil and Pan! Very Dangerous!!

...I once used a Holley Mech pump! The Chrome One! Left me stranded when one of the two internal check valves, popped out of it's counterbore.
I went to a Electric Holley Pump, the red low pressure one. Have had No problems since and has run a Solid 6 PSIG...

The only other reason for Fluctuating Fuel Pressure..would be a 'Waterlogged' Float! Float doesn't float, needle stays open/off the seat, fuel is pumped through the Carb, flooding the Engine..AND! The gauge Never reads above Zero - 1, because the Flow is never restricted! The 'Head' of Pressure is Never Built Up!! Pressure is only produced when a flow of liquid is Restricted. Pumps DO NOT Produce Pressure!! They Produce a Flow!! There are NO 'High Pressure' Pumps! They are 'High-Flow'-'High Volume', Pumps!

There is also the Chance of a Blown 'Power Valve'!! That Will produce the same symtoms!! I have come across this more than once in My lifetime!...