Register now to get rid of these ads!

Technical What auto tranny

Discussion in 'Traditional Hot Rods' started by johnrfray, Nov 14, 2019.

  1. What automatic tranny are you guy s putin behind your 48 flathead truck
     
  2. mgtstumpy
    Joined: Jul 20, 2006
    Posts: 7,623

    mgtstumpy
    Member

  3. 40Standard
    Joined: Jul 30, 2005
    Posts: 5,741

    40Standard
    Member
    from Indy

    I like a turbo 350 tranny
     
  4. Hard to beat the Ford C4. Unless you are in need of an Overdrive, then the Ford AOD works well if you have a well built flathead. Most stock flatheads have a hard time pulling an OD, especially in a truck with a less than optimal drag coefficient.
     
    Register now to get rid of these ads!

  5. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,747

    Ebbsspeed
    ALLIANCE MEMBER

    I don't have a 48 flathead truck, so......
     
  6. For a automatic behind a flathead you would be hard pressed to find anything that works better than the good old C-4. HRP
     
    OLSKOOL57, ted kovacs and 1934coupe like this.
  7. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,135

    porknbeaner
    Member

    I am a big fan of the turbo 400 in a truck, but not behind a flatty. They take too much torque for a flatty to spin and still perform.

    In a flathead truck (any year) if I was going to use an automatic I would use a Ford C4. Easily adaptable to almost anything, lots of pieces to beef one up if need be, small light and not a resource hawg.
     
    Chavezk21 and 1934coupe like this.
  8. 1934coupe
    Joined: Feb 22, 2007
    Posts: 3,429

    1934coupe
    Member

    I'm a GM guy and a 400 fan but I'm also smart, if the Ford and flat head guys recommend a C4 that's what I would do in an instant. No sense in reinventing the wheel.

    Pat
     
    Chavezk21 likes this.
  9. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 2,374

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    C4 behind my Flathead.
     
  10. What year c4
     
  11. What year C4 ?
     
  12. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 2,374

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    Mine is a 1967-70

    There are a few adapter kits on the market. I purchased mine from Speedway, $400. Others are up to $800.
    Check them out to see what suits you.
     
    porknbeaner likes this.
  13. porknbeaner
    Joined: Sep 12, 2003
    Posts: 41,135

    porknbeaner
    Member

    They have not really changed much since '64. I would look for a newer one just because it is more likely to have some life left in it.

    I had one in a '68 Torino that was about indestructible. I went to a big block and sold the Windsor and tranny to another guy who wore out a couple of small blocks with it.
     
  14. ekimneirbo
    Joined: Apr 29, 2017
    Posts: 369

    ekimneirbo
    Member
    from Brooks Ky

    A few things to think about.
    When you run the large heavy duty transmissions like a 400 Turbo or comparable, they will take a lot more HP to operate and a flathead normally doesn't have excess hp to waste.

    A three speed automatic will have a higher first gear, so you may need to use a lower geared rear end to have decent acceleration......not talking race acceleration. That will in turn affect driveability if you get on the xway. Nothing is more annoying than driving somewhere with an engine running a high rpm.

    An overdrive of almost any type will give you a lower (higher numerical ) first gear, AND an overdrive gear for the xway..........making your vehicle much more pleasant and efficient.
    You get better low speed acceleration and lower cruise rpms on the xway.

    Given the lower power numbers of a flathead I think the most enjoyable transmission will be a lighter duty overdrive transmission. I think one of the biggest decisions any builder makes is what transmission he puts in the car. Many people don't want to drive to shows because they don't have good over the road capability. Take your current daily driver and get on the xway and hold it in 3rd gear for a few miles and see the difference OD makes.
    https://www.speedwaymotors.com/Flathead-V8-to-Ford-AOD-Transmission-Conversion-Kit,25353.html

    Looks like an easy to make adapter or can probably buy just an adapter if you can get your own tranny.
     
    Last edited: Nov 16, 2019

Share This Page

Register now to get rid of these ads!

Archive

Copyright © 1995-2020 The Jalopy Journal: Steal our stuff, we'll kick your teeth in. Terms of Service. Privacy Policy.

Atomic Industry
Forum software by XenForo™ ©2010-2014 XenForo Ltd.