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Technical Mating a slant pan hydramatic to a '57 371 Olds motor

Discussion in 'Traditional Hot Rods' started by spacecowboy81, Jun 28, 2019.

  1. spacecowboy81
    Joined: Dec 9, 2012
    Posts: 67


    The slant pan didn't come in 1957s, the jetaway did. I took separated my 1949 303 engine and single range hydramatic but I can see this 1956 transmission and 1957 engine are a bit different or may be I'm missing a part. I can't find quite enough pictures or diagrams on the web or the forum to help me but I have the flex plate from the '57 and the flywheel I can't remember at this point which engine that came off. :rolleyes: Either my 394 or this 371. But whats missing here? Seems like this flywheel with the spring mechanism in the center is not right for this setup because the splines on the inside don't have anything to mate to? All the challenges of building an early Olds engine I believe I averted with the help of this forum and I can't wait at this point to drive this hot rod so hope I can figure this out fast.

    20190628_200507.jpg 20190628_200447.jpg 20190628_200436.jpg 20190628_200441.jpg 20190628_200529.jpg
  2. bob3757
    Joined: Sep 26, 2008
    Posts: 158

    from Tigard, Or

    In 1963, I installed a B&M dual range hydro in my 1950 Olds, with a 1957 Olds J2 engine. The 1957 and later engines are externally balanced. You need an early flywheel/flexplate, with weight welded on to match the later flexplate. I bought mine, at the time, from B&M, of course that was 55 years ago ! Bob
  3. spacecowboy81
    Joined: Dec 9, 2012
    Posts: 67


    So I need an early flywheel weighted to balance the externally balanced '57 engine. That I'm getting so far. I'm a little lost with what the shaft on the hydramatic goes into. The '57 371 crank has a large cavity compared to the crank on my '49 303 engine. On the '49 the transmission shaft fits tightly into the crank with a hole thats nearly the same size. This flexplate here that came with the slant pan transmission has splines. :confused: Also, that splined part with the springs wasn't on my '49 torus at all. Another hamb member told me I just need a pilot bearing to go in there. What specifically, where can I get it, or do I need to manufacture a part to mate this combination?
  4. saltracer219
    Joined: Sep 23, 2006
    Posts: 631


    You will need to have a oilite bronze bushing made to pilot the early Hydro input shaft in the 57 crank. You do not use any of the 57 transmission or flywheel parts. As has been said you must have the early flywheel counterweighted to match the 57 .
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  5. Todd553
    Joined: Feb 16, 2005
    Posts: 461


    This from my old B&M catolog.
    H380 likes this.
    Joined: Mar 21, 2014
    Posts: 395

    from okc

    Wow, that's cool....
  7. spacecowboy81
    Joined: Dec 9, 2012
    Posts: 67


    Okay this is making good sense, thanks all. I'll just track down the right dimension oillite bushing and have the crank bored to fit it.
  8. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,122


    I think that you get the bushing to fit the shaft and turn the o.d. down to fit the crank. Seems to me that is what my dad did for me back in 1964.
    I think that the pilot bushing was '39-55 Olds. I do remember that to buy the B&M one was about $9.00 and the local parts store was $.89.

    That was a looooong time ago!
  9. I did this a long time ago on a 394 swapped into a '50 Ford panel. Used the early torus cover, bell-housing, block plate and starter. Then had the back of the crank bored to fit the early Hydro pilot bushing. And like everyone's said you'll have to deal with the balance issue...

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