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Pro Flo and Pro Flo 2 questions

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  • Pro Flo and Pro Flo 2 questions

    Newbie here:

    I am working on a 68 Firebird with a ZR-1 V8 for a customer. The customer bought the car, engine and Pro Flow system about 10 years ago and now is having me finish the build. (arrrgh) The owner wanted a Trans -Am shaker type hood so i fabbed one to work with the Pro Flo system on the car. Now we discover that the Pro Flo system is hopelessly out of date, and a newer system will not work with the (highly desired by the customer) shaker air intake. So we are determined to make the old system work. We were missing a lots of the original Pro Flo wiring harness and through some miracle, the owner sourced me a new complete harness and electronics for a Pro Flo 2. I have figured out all the connections except a few.

    I know I need the air temp sensor for the air cleaner (part 3588) which is in stock and available.

    I do not have the ignition coil that came with the original Mallory distributor, does anyone know what ohm coil I need to use???

    Also there is a vacuum valve attached on the drivers side front fuel rail (see picture). Based on the pictures supplied with the new harness, this is not used on the PF2. I should have fuel regulator 1729 and install it in the cross over line between the fuel rails on the rear side, right? Then the fuel line from the pump tees into the crossover line on the front side between the fuel rails. The return line to the tank is the bottom port on the regulator. I size the fuel pump based on the HP chart in the manual, then set fuel rail pressure using the regulator 1729.

    Can anyone tell me if i have that right??



  • #2
    For an ignition coil you can run a MSD Blaster 2.

    The vacuum valve on fuel rail is the fuel pressure regulator. It is a GM type fixed pressure regulator that is most likely 43 psi. So that eliminates the need for any other regulator. You will need to run a -6 return line from the brass fitting back to the gas tank.


    • #3

      Thanks for your response.

      I assume from your answer that the supply from the fuel pump would connect to the opposite fuel rail, then the "discharge" of the vacuum regulator is the return? Or is it the other way around?



      • #4
        Is there any reason that i can't plumb the fuel supply through an adjustable regulator directly to the fuel rail "loop" sot of like you would do with a carb set up? Certainly would simplify piping and seem to me if I have sufficient fuel (psi and gph) from the fuel pump and a properly sized regulator that this set up would deliver constant pressure to the fuel rail(s). Am I missing something??


        • #5
          You can do that but it really isn't much different from this setup is it? With the setup you have now, all you need to do is supply fuel to the rail without the regulator and then run a return line out of the regulator back to the tank. If you ditch the rail mounted regulator and use an external one like the 1729, you plumb one side as the fuel supply into the regulator and then you plumb the other side as the out to the fuel rails. There would be a a single inlet on one rail and the other rail would be capped off basically giving you a "dead head" setup. You would still have to run a return line out of the regulator back to the tank. Six of one, half dozen of the other. Same but different, different but the same. You can set it up either way - it won't make a difference except you'll have to buy another regulator and more fittings if you decide not to use the rail mounted regulator.


          • #6

            Maybe something like this???

            Just confirm what fuel rail inlet thread sizes ....will fit different eng. & applications...Many choices/options available.

            Buy Russell 644033 at JEGS: Russell EFI Regulator to Fuel Rail Adapter Fittings Swivel Design. Guaranteed lowest price!
            Last edited by 2700 Cast; 01-16-2019, 08:02 AM.


            • #7
              Thanks for the feedback guys. I'll keep you posted.