Fuel Pressure??

I am getting 5 1/2 lbs of pressure with a new 780 Holley Street Avenger. Is this enough?

The engine is a 383 with 10.6-1 compression, Vortec heads massively ported, Victor Jr matched intake, Summit electric fuel pump and regulator. The 2nd line on the reg. is now a return line to the tank. Before, it would dead head after running for a second or two the pressure would go from 7 to burying the needle. After running the return line, it got to where it wouldn't peg it out but now the most I can get is 5 1/2 lbs.

I am running 6AN lines to & from the tank. If I changed the return to 4AN would it help? Would it increase the pressure enough to make it adjustable? I really would like about 6 1/2. Does that sound about right?

Thanks



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69 RS Camaro (383,350t,12-bolt w/3.73s)
79 WS6 Trans Am (406SBC,factory 4-spd,3.23 posi)
87 GTA Pace Car Clone (350TPI,700r4,140k miles)
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I'm assuming you changed to a return style regulator right? (a dead head type will not work with a return line).
if so, then I would try plugging the return line (unscrew the return line somewhere and put your finger over it.) and see if you get more pressure. (then put it back) If so then make sure your regulator is adjusted all the way to the highest pressure (maybe try turning the adjusting screw counter clock wise also and see if the pressure goes up, some work backwards) If you could not get any more pressure out of it by blocking the return line, then there is something wrong with your feed. Possibly pump not strong enough, lines not big enough, or a restriction, but something not allowing enough fuel to get the correct pressure.

oh, one more thing, I just remembered that a pump set up for a return style regulator sometimes puts out more pressure than a dead head style pump. See if your pump has an internal pressure by pass (the Mallory 110 and 140 do) What that does is limit the pressure of the pump output for use with a dead head regulator. On mine I had to pull out this bypass valve and spring so the full pressure goes out of the pump. This was recommended for use with a return style system.

check out this page for a lot of fuel system info:
http://www.centuryperformance.com/fuel.asp

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69 Camaro (http://web.tampabay.rr.com/yz250/camaro.htm) among other toys.

[This message has been edited by yzguy (edited June 13, 2002).]