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Technical flathead fuel lines

Discussion in 'Traditional Hot Rods' started by gdrummer, Mar 2, 2025.

  1. gdrummer
    Joined: Jul 9, 2018
    Posts: 258

    gdrummer

    hi,
    working on a 36 ford PU with a 8BA flathead.
    it has 2 stromberg 97s and i want to change the rubber fuel lines running from the pressure regulator to the carbs to hard lines.
    my question is what size and material would be best?
    thanks
     
  2. jimmy six
    Joined: Mar 21, 2006
    Posts: 16,251

    jimmy six
    ALLIANCE MEMBER

    5/16” flare tubing will be more than enough. But 1/4” will be fine also. I’m not sure what Stromberg fittings are available. If your fuel block is on the firewall be sure to make a few vibration curls.
     

    Attached Files:

    Last edited: Mar 3, 2025
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  3. Fortunateson
    Joined: Apr 30, 2012
    Posts: 5,612

    Fortunateson
    Member

    I think that the 14” may be a little too big... Perhaps 1/4” might be better?
     
    Last edited: Mar 4, 2025
  4. I'd recommend using some NiCop material - much easier to bend and doesn't corrode. You'll only need 5/16" lines, though you might like the looks of 3/8" a bit better. As noted above, if you're using a fuel block and it is on the firewall, then you either need a bit of rubber fuel line at the start, or some vibration coils to allow the engine to "move" and not crack the hard lines.

    Note: With just two Strombergs, you can run a single line from your fuel pump and continue it from the first carb to the second - there is no real reason to run TWO lines and it will look better with one. The key is to have the right fittings at the carbs.
     
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  5. Bearing Burner
    Joined: Mar 2, 2009
    Posts: 1,184

    Bearing Burner
    Member
    from W. MA

    Braided stainless steel and AN fittings
     
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  6. tubman
    Joined: May 16, 2007
    Posts: 7,610

    tubman
    ALLIANCE MEMBER

    Remember, this is a traditional Hot Rod site.
     
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  7. alanp561
    Joined: Oct 1, 2017
    Posts: 5,140

    alanp561
    ALLIANCE MEMBER

    Charlie at Vintage Speed has all the parts for the single line set up and it does look good. The polished stainless version looks even better.
    [​IMG]
     
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  8. Jeff34
    Joined: Jun 2, 2015
    Posts: 1,116

    Jeff34
    Member

  9. I do not like the aluminum fittings with the nylon washers . . . have seen the washers distort and fuel leak all over the place. I prefer the higher quality stainless ones that Stromberg makes - you can get them at Summit Racing. They're not cheap . . . but neither are eggs these days! LOL

    Stromberg Carburetors 9082K Stromberg Banjo Fittings | Summit Racing
     
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  10. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 14,067

    Bandit Billy
    ALLIANCE MEMBER

    There's always "that guy" :cool:
    Reminds me of Adam Sandler showing up at the Oscars in athletic shorts and a hoodie the other night..
     
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  11. lostn51
    Joined: Jan 24, 2008
    Posts: 2,462

    lostn51
    ALLIANCE MEMBER
    from Tennessee

    Yeah but they make black braided line and use the black fittings to match.
     
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  12. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 14,067

    Bandit Billy
    ALLIANCE MEMBER

    Yes they do and I use it on my cars. I use the 6AN black nylon shielded and black fittings. I like to strip the flats on the nuts and polish them to contrast. I have to admit, I used those red and blue fittings on braided steel back in the day. The velocity stacks really needed them.
     
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  13. nochop
    Joined: Nov 13, 2005
    Posts: 4,314

    nochop
    Member
    from norcal

    I used jic fittings. I got them at my local hydraulic hose shop. Very cost effective IMG_5610.jpeg IMG_5608.jpeg
     
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  14. CME1
    Joined: Aug 10, 2010
    Posts: 329

    CME1
    Member

    That is a very professional and clean looking gas supply line to your carbs.
     
  15. deucemac
    Joined: Aug 31, 2008
    Posts: 1,587

    deucemac
    Member

    That reminds me of when I worked flight test for Douglas Aircraft many years ago. I was given the task of fabricating pressure transducer lines to monitor brake pressure on the C-17. I am up in the wheel well with my tube benders, flaring tool and stainless tubing. I am fabbing line to one of the wheel brakes when this guy walks up and asks me if I was a " tuber". I told him no, that I was in flight tst and outfitting the brakes with pressure transducer for our flight test instrumentation. He than said he thought I was a tuber because of the ease at which I was fabbing up the tubing, and he wondered where I learned to do that. I told him that I was a hot rudder and learned over years of building brake, fuel, and cooling lines. He was amazed that that skill could transfer to aircraft! I told him that tube was tube and only the material and location made the difference on how it was installed. He just shook his head and walked of. Being a dumb kid without much money forced me to learn many fabrication skills. Toʻ many people lock into a particular skill and don't realize that the skill is transferable to other equipment and systems. I remember when I went to work on the B-1B program and people asked where I came from. They were surprised when I said I came from a Ford store! When I explained that I was just a mechanic, they were confused. At the end of the program with no aircraft work in sight, I was asked what I was going to do. I replied that I was going to go to work at a Ford dealer and the same people that shunned me when I started where aghast because I was going to work on cars! You can't do that, they said you're an aircraft mechanic! I told them the same thing as I did when I first started "I'm a mechanic". It's a shame when people lock themselves in to a narrow version of their skill sets. Almost ever built uses some if not all of the same systems. The difference is how those systems were adapted to their particular operation. Learn system function and you will be able to see how it was adapted to for there requirements. Think outside the box! That's how most things came into being!
     
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  16. Great post! I think exactly like you do!
     
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  17. nochop
    Joined: Nov 13, 2005
    Posts: 4,314

    nochop
    Member
    from norcal

    A good book helps too 67590577332__13E1477D-1EA9-4DEA-8692-E027E247EEAE.jpeg
     
  18. Tow Truck Tom
    Joined: Jul 3, 2018
    Posts: 2,805

    Tow Truck Tom
    Member
    from Clayton DE

    :)Can anyone tell me why my semi educated brain tells me that,
    the more un-anchored weight there is,, the more vibration-reaction will be occurring?:)
    :) and BTW the harm takes time but there is no warning
     
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  19. deucemac
    Joined: Aug 31, 2008
    Posts: 1,587

    deucemac
    Member

    To bad that I never knew about that book until just now. It could have saved me countless feet of wasted tubing and enormous frustration! Not to mention the expense of the tubing! But, I am proud of what I learned and what I was able to accomplish!
     
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  20. Having high quality flaring tools is a must as well . . . make a huge difference - and is mandatory for brake lines.
     
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  21. stubbsrodandcustom
    Joined: Dec 28, 2010
    Posts: 2,526

    stubbsrodandcustom
    ALLIANCE MEMBER
    from Spring tx

    1/4" works flawless for the flatty.

    34-92.jpg
     
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  22. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 14,067

    Bandit Billy
    ALLIANCE MEMBER

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  23. Jeff34
    Joined: Jun 2, 2015
    Posts: 1,116

    Jeff34
    Member

    You could go all out and build a CAD model of the proposed fuel line, and then analyze it for it's first or "fundamental" frequency as well as the higher frequency multiple harmonics at the same time. That would give you a good "theroetical" idea if it might fail.
    WAY overkill for a simple fuel line, but probably a fun exercise.
     
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  24. stubbsrodandcustom
    Joined: Dec 28, 2010
    Posts: 2,526

    stubbsrodandcustom
    ALLIANCE MEMBER
    from Spring tx

    Thanks Billy! Got em from Noble Speed. He has some killer stuff.
     
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  25. nochop
    Joined: Nov 13, 2005
    Posts: 4,314

    nochop
    Member
    from norcal

    I did flex line from carb to regulator, used tube lock crimped fittings IMG_7289.jpeg IMG_5609.jpeg
     
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  26. CSPIDY
    Joined: Nov 15, 2020
    Posts: 793

    CSPIDY
    Member

    They have been using AN stainless steel braided hoses on military aircraft since ww2
    from what I have seen using aircraft parts on Hotrods was very common in the 40s and 50s
     
  27. tubman
    Joined: May 16, 2007
    Posts: 7,610

    tubman
    ALLIANCE MEMBER

    Not where I came from. Perhaps in Southern California with it' s aviation industry and veterans who had been mechanics during the war, but in the rest of the country, we weren't even aware they existed, and even if we did, AN fittings would have been unavailable. There was no internet or 1-800 infrastructure back then.

    We worked out of J.C. Whitney and Honest Charlie catalogs back then, and I don't remember ever seeing them.
     
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  28. It's beyond my pay grade to help you with the degrees of vibration-dampening effect using curly hardlines. The traditional way to quell vibration is to incorporate rubber in the clamps, hold-downs, and stand-offs....... but I've never seen anyone try that on fuel hardlines for some reason.
    Ever since I was big enough to see over the fenders and into the engine compartments, I just assumed that the flexible sections between the hard fuel tubing sections was to deal with engine torque. I've seen engines twerk about more than a halftime hip-hop show just from tapping the throttle pedal.
    So I'm with you on wondering about the "vibration theory".
     
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