1/2 inch fuel line

Discussion in 'Engine Topic' started by rhino370, Jan 5, 2017.

  1. rhino370

    rhino370 Member

    Oct 18, 2006
    have read everywhere that you need 1/2 in line to support 700hp, yet 90% of the fuel pumps and regulator fittings are 3/8, doesnt that restrict the whole thing ?
  2. muscl car

    muscl car Veteran Member Lifetime Gold Member

    Not unless you get a fuel pump with 1/2" Dia fittings
  3. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member


    Some of it is about volume, and how quick the recovery is.
    A small line has very little volume, a larger line has volume and can catch up quickly.

    73 Z likes this.
  4. Notalent

    Notalent Veteran Member

    Jan 27, 2010
    If you go with that 1/2" fuel line, keep in mind the volume that's added and a higher flowing fuel pump is needed.
  5. Notalent

    Notalent Veteran Member

    Jan 27, 2010
    Those larger fuel pumps will have the larger inlet sizes for it as well, like the Holley 12-454-20 170GPH will have -8 inlets (1/2")
  6. rhino370

    rhino370 Member

    Oct 18, 2006
    those are mech fuel pumps im looking for elect , confused how they say support 700hp yet dont have the large fittings to supply fuel to do it
  7. Rene Melten

    Rene Melten Veteran Member Lifetime Gold Member

    Sep 22, 2007
    Blind Bay, B.C.
    Small fittings = need higher pressure. Large fittings = need higher volume.
    Just saying.
  8. 77 cruiser

    77 cruiser Veteran Member

    Nov 17, 2006
    Frostbite Falls MN
    3/8 NPT the OD is .675.
  9. 450bench

    450bench Veteran Member

    Feb 25, 2002
    memphis, tn-shelby
    Quick story about 1/2 inch fuel line.
    Years ago I had a nice 72 Vega. 11 to 1 LT-1 motor with Ultradyne 255/263 626 solid roller. Car ran 6.90s all day. 3/8 fuel line with one Holley blue pump, original z28 intake and original 4490 780 Holley. Brookshire told me to run 2 blue pumps and 1/2 fuel line, along with 2 regulators. He is a brilliant guy, really is, so I tried it wanting to go faster. Spend the money and did it. Car ran exactly the same. Exactly.
    Obviously all situations are different but wanted to share the story.
  10. G72Zed

    G72Zed Veteran Member

    Sep 8, 2015
    good story thx for sharing that 450bench

    That Says allot on what is actually needed for fuel volume/supply, a 10.90 car with only 1 blue Holley and 3/8 line was enough to supply all the fuel that the engine required, and then some.

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