Mechanical fuel pump suggestions and input on going from 3 lines to 2

Discussion in 'Carb Fuel Systems' started by Bullet Bob, Dec 1, 2018.

  1. Bullet Bob

    Bullet Bob Junior Member

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    My truck is an 1980 Chevy C20 with a 454 that was transplanted in the early 80s, and a standard transmission. It had been sitting up for at least 8 years with both tanks full of fuel. Since I finally got both tanks emptied today using the mechanical pump, and running the motor off a jug. I decided to replace the tanks instead of reusing them. That way there is no doubt of their condition. Since I'll be replacing soft lines and blowing the hard lines out after letting some marvel mystery oil sit in them a few days. Should I go ahead and put a new higher output pump on, and should I get one without a return line? Do plan on getting a different carburetor to replace the quadrajet later on.
     
  2. PrairieDrifter

    PrairieDrifter Full Access Member

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    Your fuel pump pressure and setup will be the same for different carbs. I would stick with a regular stock output mechanical pump.

    My theory on the return line is the fuel pump probably isn’t taking every last drop of fuel that it’s pulling up, and when you kill it there’s fuel still sitting in the line and pump, I feel like a pump with a return line would last longer with what I think would be less strain on it.

    I can here fuel draining back in the tank right away when I kill my engine in my burban. I don’t think it causes longer startups, I may be wrong though. I have ran both styles though
     
  3. 75gmck25

    75gmck25 Full Access Member

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    The return line allows excess fuel to return to the tank, which keeps fuel circulating, and it generally keeps the fuel cooler. If you use a two port pump, some folks have had problems with high fuel temps in hot weather, which make the truck run poorly and/or vapor lock. If you are replacing a three port pump, I recommend using the same type of new pump.

    Bruce
     
  4. bucket

    bucket Super Moderator Staff Member

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    I've found that the stock pumps used on the 454's are barely adequate. I've replaced one with a higher output model from Jeg's (no return port) and have not had any issues with it. Most driving is done in hot weather.
     
  5. Craig 85

    Craig 85 Supporting Member Supporting Member

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    Wix makes this 3 way fuel filter #33041 (3/8”, 3/8”, ¼” vapor) if you run a 2 port pump.

    [​IMG]
     
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  6. bucket

    bucket Super Moderator Staff Member

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    How does that work? Is there an internal regulator that sends the excess fuel into the return/vapor port?
     
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  7. Bullet Bob

    Bullet Bob Junior Member

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    Thanks for the replies. Think I'm going to stick with the 3 hole pump for now, and will do some research on that filter incase I decide to go to a 2 hole and save me so time with the plumbing on fuel lines. Won't be ordering my tanks and pumps until my next paycheck. Hit a deer in my daily driver and I'm using my fun/toy fund to pay my deductible to fix all that mess.
     
  8. Craig 85

    Craig 85 Supporting Member Supporting Member

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    I'm not really sure. I would assume like my 3 port fuel pump. It just returns extra fuel not going to the carb. It would probably help with heat soak and vapor lock. I found this one day when I was looking for fuel pumps for my truck. I believe it was used on Mopar engines.
     

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