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Fhead Rpm

Discussion in 'Early CJ5 and CJ6 Tech' started by Jrobz23, Sep 16, 2020.

  1. Sep 17, 2020
    CHUGALUG

    CHUGALUG Member

    Silverton, OR
    Joined:
    May 11, 2019
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    238
    The Dodge 218 flat head 6 has the same stroke as our 134's and was back in the day used for Stock car racing LOTS of speed equipment was available. I had a 1940 Dodge 5 window coupe with the 218 stock with a better carb it would do 100mph had 3.90 gears on L78 tires (about a 29" tire) don't remember the rpms but it was approx 4500 based on the speed calculator.
     
  2. Sep 17, 2020
    Glenn

    Glenn Kinda grumpy old man Staff Member

    Apopka, Fl
    Joined:
    Sep 21, 2002
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    12,367
    I've never run an F-head without a fan so I've always wondered how it would sound at say 3,000 rpm or so without one. Not that I am even remotely thinking of trying it of course.
     
    Jrobz23 and ITLKSEZ like this.
  3. Sep 17, 2020
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
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    Aug 13, 2015
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    If you want to hear one run at 7k, the Grundsow will be coming out of retirement for the 50th anniversary running of the Line Mountain 7 Miler in Dornsife, PA this Saturday. I wish I could make it.

     
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  4. Sep 17, 2020
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Aug 10, 2003
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    A fair point, but I would not make any conclusions without comparing the bearing area of the journals. If the Dodge journals were wider or larger diameter than the F134, that would be an important difference. Piston design should matter too. The 134 piston is about 10% smaller in area. Significant? I don't know.
     
  5. Sep 18, 2020
    CHUGALUG

    CHUGALUG Member

    Silverton, OR
    Joined:
    May 11, 2019
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    238

    Glenn when I get mine running I will post a sound clip of it at 3000rpm as I will be running a pair of electrics unless the engine is hot they won't be running (I also have a way to manually turn them off) Its a 134L but I bet it sounds pretty close to the same as an F
     
  6. Sep 18, 2020
    Keys5a

    Keys5a Sponsor

    Florida Keys
    Joined:
    Jan 23, 2014
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    4,170
    For what its worth, the cranks in the race Jeep engines are the ones with the bolted counterweights, not one-piece. Are these from the earlier L-heads?
    -Donny
     
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