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Technical 8ba to AOD

Discussion in 'The Hokey Ass Message Board' started by 30Caliber, Nov 4, 2020.

  1. 30Caliber
    Joined: Jul 29, 2017
    Posts: 52

    30Caliber
    Member

    Two years ago I purchased the Speedway adapter kit to mate AOD transmission to 8ba mercury flathead block. My crankshaft is 49 mercury 4" stroke. The issue I'm having is I have to pull the torque converter forward out of the pump to bolt up to the flex plate. The AOD is 1987 model with the original TC. Has anyone run into this issue and how do I correct. It took me two years and numerous blocks to find a good one to rebuild.
     
  2. sdluck
    Joined: Sep 19, 2006
    Posts: 3,332

    sdluck
    Member

  3. 30Caliber
    Joined: Jul 29, 2017
    Posts: 52

    30Caliber
    Member

    Speedway was my first call and they referred me to Performance Automotive, neither had an answer. PA suggested I purchase a new TC and compare to the one I have.
     
  4. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 4,028

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    No idea here. My trans is a stock C-4 using the Speedway adapter.
    I know Speedway offers two sizes of flywheel but I don't know if that's a fix for you or maybe you have the wrong kit? Or maybe the block plate is installed incorrectly? Not seated?
    Over the years it was easier for me to place the TQ on the flywheel before installing the trans but you have to be precise or you'll break the pump during install.
    It makes a very distinct sound when that happens...."PING" with a slight echo...You'll never forget what it sounds like...
    Here is a part number to look up. It might help you out a little bit. Also includes the AOD Trans.
    Flathead V8 to Ford AOD Transmission Conversion Kit
    Sku # 91028907
    Mfr. Part # 91028907

    Or, Speedway Part # 91628901 (Adapter Kit w/o Trans)
    • Fits 1949-1953 Ford 8BA and 8CM Mercury Flathead V8 engines without integral bellhousing
    • If the bolt pattern on the front of the torque converter is a 10-1/2" circle, order the 157 tooth version.
    • If the bolt pattern on the front of the torque converter measures 11-1/2", order the 164 tooth version.

    Wish I could help you out.
     
    Last edited: Nov 4, 2020
  5. 30Caliber
    Joined: Jul 29, 2017
    Posts: 52

    30Caliber
    Member

    Flathead Dave, I purchased the 91628901 kit w/o transmission. I had already sourced a 1987 AOD with its TC. I had mated the TC to the transmission and made sure it was in the pump correctly and then mated to motor. I knew I was in trouble when I had to pull the TC forward to get the TC bolts to start in the flex plate. If I had a 1/2" adapter plate between the crankshaft and flex plate it would work.
     
    Flathead Dave likes this.
  6. ronnieroadster
    Joined: Sep 9, 2004
    Posts: 1,162

    ronnieroadster
    Member

    If it was even possible to move the flexplace the 1/2 inch difference I think the next issue you would have is the starter not engaging the ring gear teeth. Couldn't you make spacers to go between the converter and the flex plate? You wrote about torque converter bolts if that's how its mounted longer bolts should work. As long as the converter pilot is still locating in the crank shaft that should work fine.
     
  7. Budget36
    Joined: Nov 29, 2014
    Posts: 15,013

    Budget36
    Member

    How far did you have to move the TC?
     
  8. 30Caliber
    Joined: Jul 29, 2017
    Posts: 52

    30Caliber
    Member

    Ronnieroadster, I miss spoke not bolts on the TC, but the studs on TC. There are two early 70's starters one with short gear, and one with longer gear. I removed the starter from a 1974 Ford 400 motor I have and it was the longer gear. It appears if there was a spacer between the crankshaft and flex plate it would all mesh. The instructions just said early ford starter. Will have to pull the motor and do some troubleshooting.
     
  9. Flathead Dave
    Joined: Mar 21, 2014
    Posts: 4,028

    Flathead Dave
    ALLIANCE MEMBER
    from So. Cal.

    I used a starter from a 1966-70 289.
    My flathead starter bolted right up and worked with no problems.
    Hope this gets fixed for you.
     

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