1966 engine with 1981 904A

Discussion in 'Slant 6 Engines' started by drauhut, Aug 12, 2018.

  1. drauhut

    drauhut Member

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    I have read 1967 and older slants cannot be used with 1968 and newer 904's without some modifications to end of crankshaft, or the plate..does anyone know if it just doesnt fit or whether it just works incorrectly?

    Im asking because i have a 1966 engine( modified by other with very little info(casting number-2463430-17) and a 1981 904A (PK4202662X) ..i have put 200 miles or so on it, and previous owner said he had 600 miles on it.
     
  2. Darter6

    Darter6 FABO Gold Member FABO Gold Member

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    The 67 and earlier Slants have a smaller crank register. 68 up are larger. Thus a newer 904, like yours the torque converter has a larger "snout" and won't fit into the earlier crank. Now the crank may have been machined to fit the newer converter, OR a custom converter was made. I mated a 71 904 to a 67 crank by having Hughes transmissions make a converter with the smaller snout. The front pumps are different along with the input shaft starting in 68 for the 904 transmissions both in the Slant and the V8.
     
  3. drauhut

    drauhut Member

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    S
     
  4. drauhut

    drauhut Member

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    Thx for replying.
    So if im driving it, and it runs fine( had it to 70 mph) then its probable its been modified then, correct?
     
  5. Darter6

    Darter6 FABO Gold Member FABO Gold Member

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    If not it wouldn't be driveable. Someone musta' did it right before you bought it. Have fun !
     
  6. drauhut

    drauhut Member

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    Thank you kindly
     
  7. cosgig

    cosgig MoBro Inc. FABO Gold Member

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    I would be worried if it were the other way around and they used a later motor with an early trans. But your situation sounds like someone already remedied the mismatch!
     
  8. Darter6

    Darter6 FABO Gold Member FABO Gold Member

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    Cosgig is right. The opposite, you need a bushing for the crank to use the early trans. I've seen it done without but the flex plate will crack after awhile along with other things.
     
  9. drauhut

    drauhut Member

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    Thank you cosig..i appreciate the info
     
  10. cosgig

    cosgig MoBro Inc. FABO Gold Member

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    Wallered out the front pump on a car I bought with a 72 motor and the original 66 trans. And, it’s the original trans for the car, and coded for a HP application, so I feel the need to rebuild it.
     
  11. drauhut

    drauhut Member

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    Thx Darter6. That means my 1973 904 is a suitable back up
     
  12. Slantsix64

    Slantsix64 Well-Known Member

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    I once bought a dart from some guys who used a bunch of washers to try mate up the early motor with later trans, i was very confused but for $300 bucks what could i say.
     
  13. Slantsix64

    Slantsix64 Well-Known Member

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    the previous owner probably had a custom converter made to be able to mate the 66 block to the 68 and up trans, but if you have a later motor and early trans Charlie S sells the crank adapter.
     
  14. drauhut

    drauhut Member

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    Thank you