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What size gears?

Discussion in '40- & 55-Series Tech' started by godzilla, Sep 12, 2003.

  1. godzilla

    godzilla

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    I have a 74 fj40 that I'm doing a soa and a disc conversion on. I fiqured now would be a good time to put lockers and gears in. What ratio gears should I use. It will have 35's on it and will be driven on and offroad. I saw manafre has 5.29's available. Thanks
     
  2. Cruiserdrew

    Cruiserdrew SILVER Star

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    Well-do the math. For 35 inch tires, 4.56 gearing will give you 65 mph at 3000 rpm. 5.29 gears are weaker due to the small size of the pinion head and are really too low for these tires in a street driven FJ-40. You could even stick with the 4.11's for better highway performance, but you will give up some "grunt". In my opinion, the 4.56's would be just about perfect, assuming you stick with 35's. In your position, with soa, I would be tempted to try 37's and 4.88 gears. Check out the gear/rpm tables on the TLCA website.
     
  3. hammerhead

    hammerhead

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    What engine is being used?
     
  4. jm

    jm

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    With 38.5s, welded rear, 350tbi and an sm465 Woody's running stock 4.11s... seems to hold 55-60 fine.

    With 36s, 2f, stock 4-speed and 4.88s I've been happy, although the sm420 needs to go in to slow it down in first. It's scary to drive it above 50ish (sort of a death wobble at various speeds from unbalanced tires) so rpm's aren't an issue. Not real streetable anyway with the welded rear... tires tend to howl pretty bad turning corners.

    jm
     
  5. godzilla

    godzilla

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    It has the orginal straight six, with the 3 speed tranny and transfer.
     
  6. hammerhead

    hammerhead

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    With 5.29s and 35s you be turning over 3000 RPM at 60MPH.