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Technical Banger - T5 - rearend ratio?

Discussion in 'The Hokey Ass Message Board' started by evil clown, Oct 8, 2020.

  1. evil clown
    Joined: Jan 15, 2006
    Posts: 275

    evil clown
    from Verona, WI

    Building a ‘29 A Phaeton with my sons and grandsons. We’re trying to use parts we already have as much as possible.

    The original banger is freshly rebuilt, so we’re going to run it. We’ve got a T5 to put behind it. Our T5 has 3.97 first gear and .72 overdrive ratio.

    We were going to use the original A rearend, but it turned out to be junk. We’re are now using an 8 inch we already had.

    Finally, my question - we have two gear sets for the 8 inch, a 2.79, and a 4.10. Which would be better for all around drive ability? I think something in between might be optimal? Or could we be OK with one of these?
  2. bonzo-1
    Joined: Oct 13, 2010
    Posts: 334


    4.10 28-30 inch tall tires
  3. flatheadpete
    Joined: Oct 29, 2003
    Posts: 9,879

    from Burton, MI

    That 2.79 gear set would be an absolute turd with the banger. My Merc flatty with a t5 had a banjo with 3.78 gears and it did well. Got great mileage and accelerated rather well outta the hole.
    winduptoy likes this.
  4. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,222


    That's not an ideal trans. And the 2.79 rear gear won't work with the .72 OD. The .72 OD with the 4.10 rear gives you a 2.95 overall. Not sure how often the banger will have enough power to use 5th, but probably passable. The first gear will kill the deal. The 3.97 with the 4.10s gives you 16.27 overall. Anything over 10 or 11 things start to get gear bound and useless. You will never use 1st gear unless you want to pull a few stumps. I ran a few rear gear numbers and really can't find one that doesn't kill one end or the other.

  5. evil clown
    Joined: Jan 15, 2006
    Posts: 275

    evil clown
    from Verona, WI

    I forgot to mention, we’re running 7.50/16s, so a 31” tall tire.

    I’ve read that stock A’s have a 3.12 first gear, and most had 3.78 or 4.10 rear gears. That would make them roughly 11 or 12 overall.

    Thanks for the replies! I have no experience with a banger, and I knew there was lots of experience to draw on here!
  6. oldsman41
    Joined: Jun 25, 2010
    Posts: 1,282


    393 to 411 with 30 inch tires
  7. Tim
    Joined: Mar 2, 2001
    Posts: 11,580

    from Raytown Mo

    Another vote for 750’s and the 4:10s
    seb fontana likes this.
  8. denis4x4
    Joined: Apr 23, 2005
    Posts: 3,552

    from Colorado

    Running 3:54 in a stock A rear end with 29” tires. Engine is B with a CRAGAR head, headers, Weber 32/36 carb, electronic ignition. Car is a ‘29 CCPU weighing 2400 pounds.

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