Fuel Pressure

[car62]

i have a 358 engine, 650 carb, 110 octane race gas, 11.3:1 compression, have had carb rebuilt 3 times by 3 different builders with same results...hard to start, fuel starts pouring out vent, loads up each lap in race and smells of raw fuel, i changed fuel pump,even borrowed a known good carb and got same results...someone suggested to use a fuel pressure regulator, what kind of pressure should i be looking for? currecnt carb is a Quickfuel Technologies SS650 circle track carb with 74 and 75 jets, and high flow 6.5 power valves

[r3tracing]

5 to 6 lbs on gas should work fine

[JustAddDirt]

I believe r3tracing is on the right track.

What is the fuel pressure?
5-6-7 range is good for gas, you go over that and it will blow past needle and seat and you will experience problems you seem to be having.

is it a dual line carb or a single line?
what kind of fuel pump do you have?

[car62]

its a single line 6-an from pump to fuel log where it Y's off and goes to each bowl, just the standard chrome edelbrock fuel pump

[JustAddDirt]

Do you have a fuel pressure gauge on it?

pump may be a 7, 9 or a 13 psi. never going to know without a gauge.

does fuel log have a 1/8 pipe port in it? if so find a fuel pressure gauge at local auto parts store and hook it up. If not drill and tap fuel log for it and put in a gauge.
you may be over the psi that the needle and seats will safely take

[TBRE]

And......mechanical pumps vary up and down (they may be rated at, say 7psi, but will run from 5 to 12), like suggested, put a regulator on it.TB