Transmission difference

Engine, Trans & Driveline

  1. 1968340S

    1968340S Well-Known Member

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    What is the difference between a 2 barrel and four barrel transmission. Was on Paul Herd motor book and matched the #3515845. A727B Fits 1971 E and B bodies two barrel.
    The next #3515846. A727B Fits 1971 four barrel E and B bodies.

    Trying to match a 1969 440 with the proper transmission that will fit into my 1966 Satellite
    that had no engine or trans. The 440 came out of a 4x4 truck, but was told the the 440 was originally out of a 69 Charger.
     
  2. pnora

    pnora FBBO Gold Member FBBO Gold Member

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    For the most part little to no differences. The thing with numbers just tell you what it came from. Unless it is a virgin and never apart you will never know whats inside until you open it up.
     
  3. R413

    R413 Well-Known Member

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    There Are Definite differences. The biggest is the high gear clutch pack for a 383 2 bbl holds 3 clutches, and the 383-4bbl holds 4 clutches. Where the snap ring groove is machined is the difference.

    then there are valve body and governor differences.

    The 1971 and up are a bit better because they have a wide bushing on the high gear drum and a wide face for the bushing to ride on the stator support.

    the outside physical dimensions are the same.

    are you using the stock console shifter? Then you will need the two cast in bosses on bottom of the output shaft for the bracket to bolt to. Just under and in front the speedo housing. A pair of half round bosses with 5/16” holes about 1” apart.
     
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    • 66Satellite47

      66Satellite47 FBBO Gold Member FBBO Gold Member

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      The 727 has MANY combinations of internal components depending on the HP/torque and intended use of the vehicle/motor. There are 3, 4 & even 5 disc front drums, with a variety of numbers of return springs in the clutch pack, different front band apply lever ratios, different clutch or band materials, front or rear planetaries may have 3 or 4 pinions in either. The governor that controls the shift RPM's also varies depending on application. '71 & up use the wide bushing front drum & corresponding front pump support.
      My '70 727 that came in my 383 2bbl had a 4 disc front drum, and both planetaries were 3 pinion.
      A 727 from a 383 2bbl will work OK behind a mild /moderate 440. The comment on a console shifter are right on regarding tailshaft style.
       
      Last edited: Feb 20, 2021
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      • dvw

        dvw Well-Known Member

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        Use a 4 clutch drum if you have a 3 clutch unit. They are readily available. The wide bushing reaction shaft support/front drum is nice but not a game killer. I like the 3.8 ratio KD lever and 15 front springs for the front drum. The 3 pin planets will easily survive 800+hp. The governor weights can be machining down to reduce weight. Though the stock governor weight spring is a little stiff, it's still an a improvement. The TF2 shift kit is a nice addition. In short any 727 can easily be upgraded.
        Doug
         
      • Hilljack68

        Hilljack68 Well-Known Member

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        Wow, I never knew any of this! Do the 2-barrel vs. 4-barrel differences also apply to a 904?
         
      • pnora

        pnora FBBO Gold Member FBBO Gold Member

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        The reason I said little to no difference is because physically looking at them there is little to none. For the most part they interchange on most all big blocks. Because of the age most are not virgins and a case is just that numbers mean nothing. Rebuilders in large shops just pull them down and put all the usable parts in respective bins. They then build them to a spec that can use a variety of parts. To take a case number and assume what is inside will most likely prove interesting.
         
      • 1968340S

        1968340S Well-Known Member

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        This transmission has been on the shelf for years and it's local.
        Asking $400.00 with torque converter/flywheel.
        Probably pick it up today.
        Great information on the 727 transmissions.
         
      • toolmanmike

        toolmanmike Henchman #2 Staff Member FBBO Gold Member

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        Good question. Could be. Slant 6 cases are different and internals are lighter duty in them compared to the v8's. 340's and 360's "usually" got a 727.
         
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        • Hilljack68

          Hilljack68 Well-Known Member

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          Reason I ask is I kept the original 904 on my coronet (with factory 318 2-barrel). I yanked the 318 and implanted a 340 4-barrel. That's my current setup.
           
        • toolmanmike

          toolmanmike Henchman #2 Staff Member FBBO Gold Member

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          If the transmission is in good shape you should be fine. I would make sure the fluid and filter is fresh and the bands and linkage/kickdown are adjusted properly.
           
        • 66Satellite47

          66Satellite47 FBBO Gold Member FBBO Gold Member

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          I know there are some differences in the 904 depending on application. Not sure what they are. I've read that the "taxi" 904's had some different parts & I'd guess so did truck or van 904's.
           
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