I have a 69 camaro 350. Holley 600 DBL pump, eldelbrock airgap, mild cam. After 20 min. of running, fuel pressure gauge starts at 6lb, then slowly go"s to 0. motor starts stumbling and quits. Had a mech. fuel pump. peeps said you have vaporlock. Go to electric fuel pump. I did. Gas tank vented, all new lines, new gauge, new carb taken apart and checked. Same problem. No one here can figure out why, even with new pump, pressure go;s to 0. Need help. Thanks

 

sounds like a plugged-up filter, or the sock in the tank. i had similar problem on my 93 z-28. the car sat for years before i bought it. seems like i put a new filter on it every few weeks for a long time. i could literaly take it off and blow backwards through it, and tell it was plugged up.

 

Well, there is a new sending unit in tank and new sock. fuel filter is clear so I can see through it. Eliminated filter with straight hose. Same problem. All new hose, and stainless line running forward.