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Highest rear end ratio

Discussion in 'The Hokey Ass Message Board' started by SafariTow, Feb 21, 2010.

  1. SafariTow
    Joined: Feb 19, 2010
    Posts: 38


    Out of what car or truck will give me the highest ratio? I thought 2:42 was in something Just cant remember. Thanks
  2. SafariTow
    Joined: Feb 19, 2010
    Posts: 38


    Sorry my fault. I need a complete rear end to put under my 1930 A hot rod. Im running a 400 tranny so no overdrive. And im looking for a highway cruiser.
  3. Some cop cars from the 50's to late 70's had some high (numerically low) gear ratios.. Like 440 said, you need to be more specific to make and type of rear end.
  4. firemangordy
    Joined: Feb 28, 2007
    Posts: 307


    I've got a 9" Ford with 2.47 gears in my '41 Ford. Works great with a 327 and turbo 350. 20 mpg.
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  5. Hnstray
    Joined: Aug 23, 2009
    Posts: 11,260

    from Quincy, IL

    Tallest gears I know of is '79 Cadillac Seville......2.28 's Has 5 on 5" bolt pattern. Basically a 10 bolt GM, has disc brakes, but will accept 10 bolt drums.

  6. Larry T
    Joined: Nov 24, 2004
    Posts: 7,679

    Larry T

    A lot of the 70's Pontiac Firebirds came with high gears (2.56's, I think) in them.
    Larry T
  7. George
    Joined: Jan 1, 2005
    Posts: 7,187


    GM 2.73, ford 2.75 & Mopar 2.76 are common. I had a 79 Ford S/W with 2.25s!
  8. Unsafe6
    Joined: Dec 7, 2007
    Posts: 129


    I had a 82 Buick Regal, 10 bolt with 2.14 gears. That car could hardly get out of its own way!:)
  9. Deuce Roadster
    Joined: Sep 8, 2002
    Posts: 9,520

    Deuce Roadster
    Member Emeritus

    I suggest a V8 Maverick ... MOST were geared with a 2.79 But a 2.33 was available ... for the 8 inch Fords. With a reasonably tall tire ( like 29 inches tall ) the 2.79 would be ALL the tall gear you would want.

    Gear ratios available for the 8 inch Ford

    1 ) 2.33
    2 ) 2.79
    3 ) 2.80
    4 ) 3.00
    5 ) 3.25
    6 ) 3.40
    7 ) 3.50
    8 ) 3.55
    9 ) 3.80

    The V8 Maverick is considered the right width ( by MOST Model A owneres )
    has the common 5 on 4.5 wheel pattern and decent brakes ( with parts easy to find and BUY ).

    With the wide range of gear ratios available ...
    You should be able to gear your Model A ... any way you desire.
  10. model B 32
    Joined: Dec 11, 2009
    Posts: 45

    model B 32

    I don't know whether this is swearing or not,
    so I write a little smaller : a camaro sedan '86 has : 2.41
    when you take a decent frame with e.g. 29" tyres, 1/1 gear, so no overdrive
    2400 rpm on 2.33 gives 89 mph, 3.80 gives 55 mph.

    Last edited: Feb 22, 2010
  11. Deuces
    Joined: Nov 3, 2009
    Posts: 18,415

    from Michigan

    Some 8.8 rear ends that come in the fox mustangs and ranger pick'em ups have a 2.73 gear.
  12. oldebob
    Joined: Oct 21, 2008
    Posts: 782

    from Spokane WA

    My "other hot rod" has a 2.85 8.8 behind AOD w 351W. Really good over the road set up.
  13. mac762
    Joined: Jun 28, 2007
    Posts: 676


    I have a nice 2.77 positraction out of a 68' or 69' Le Mans.
    Joined: Jun 6, 2007
    Posts: 2,950


    In my drag RPU I use 2.47 gears in a 9" Ford. I also have a set of 2.50 gears for it.
    It hooks on pond scum.
    Runs 11s.
  15. What motor are you running, and what RPM are you looking for? My t-bird has a 3.00 rear and will cruise all day long at 70+. Not the fastest off the line, but it weighs more than double what an A does.

    Don't go so far toward highway gears that it's no fun on the street.
  16. MarkzRodz
    Joined: Sep 12, 2009
    Posts: 533


    1984 Oldsmobile Cutlass Supreme 2:41 gears.
    Joined: Nov 22, 2005
    Posts: 7,592

    from SIDNEY, NY

    A friend's 1980 Malibu had a 7.5 inch 10 bolt rear with 2.29:1 gearing.
  18. BIG APE
    Joined: May 26, 2008
    Posts: 42


    have 1978 granada rear end in a 31 model a i'm building, it has 2.46 gear. don't know how it will work, not on street yet
  19. Von Rigg Fink
    Joined: Jun 11, 2007
    Posts: 13,428

    Von Rigg Fink
    from Garage

    Love that statement:cool::D
  20. HotRodBen1987
    Joined: Jul 29, 2009
    Posts: 691


    I've got a 10 bolt GM rearend out of a 1981 buick century and its supposed to have 2.41 gears. Its in a model a tudor and worked out well
  21. Lobucrod
    Joined: Mar 22, 2006
    Posts: 4,117

    Alliance Vendor
    from Texas

    The 79 Camaro 10 bolt I put in my 50 sedan delivery has 2.41 gears. Thought it would be geared way to high but the 401 Nailhead doesnt know the difference and I get 17 MPG.
  22. I had a Monte Carlo with a 400 small block and 2:29 rear gears. The 400 would smoke the tires even with that ratio and the top end was something else....
  23. SafariTow
    Joined: Feb 19, 2010
    Posts: 38


    Thanks for all your help guys, My son and I are going to build this 30 A hot Rod Diesel truck to drive from East coast to Utah for the fun of it. I have the 4bt with the 400 allready done and ready. Looking for a good match with the rear. Again thanks for the insight.
  24. Snarl
    Joined: Feb 16, 2007
    Posts: 1,639


    what you need to do is determine what the rpm is to be at cruise, determine what the diameter of the rear tire is going to be, and then plug those numbers into one of many gear calculators that are on the internet. that will tell you what gearing you should be looking for. GM used low 2's in some of there 10 bolts as allready said, but you need to start with a target engine rpm...
  25. finally I understand why you want a low rear end. 4bt is a very low revving motor. You might want to consider something like a gear vendors overdrive. You should have plenty of torque to get a light car off the line, even with a rear in the low 2s, but it might feel a bit sluggish around town.

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