Lo-Stahl to "Higher" Stahl Converter

Engine, Trans & Driveline

  1. Nate S

    Nate S Well-Known Member

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    Here's factory #'s. 383-4, 340-4, 426-2-4 are all mopar 10.75" converters, other big blocks are 11.75". A 400-4 would have had a 10.75".
    Image1.jpg
     
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    • JG71B

      JG71B Well-Known Member

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      Awesome! Thanks! They are a lot higher than I thought they would be from the Factory. It has the low stall sticker on it so, what RPM would that be approximately??
       
    • Nate S

      Nate S Well-Known Member

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      Figure stall speed is dependent on converter design, diameter and engine torque at appropriate rpm. The 340 and 383-4 had the same converter, just the 383 had more torque, hence the higher rpm. So if your "low stall" is the 11.75 and a 400 is closest to a 383 it's probably around 2000.
       
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      • JG71B

        JG71B Well-Known Member

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        I'll measure to double-check again at lunch time but, this is a smaller 10 inch converter Im sure of and there is a spot on it where the low stall sticker was. Now I'm only assuming this was a low stall sticker because I have one in the shed with the sticker still on it and they look identical, both later 70s cast crank converters. But like I said, I'll double-check this in a little while here.
        ...
         
        Last edited: Mar 4, 2021
      • JG71B

        JG71B Well-Known Member

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        Ill leave it as is for now. It is the 10 3/4".
         
      • transman

        transman Active Member

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        This maybe of some help to you: I worked in the industry and still have a catalog on hand. From my catalog the following listings:

        Non Lockup 727: Low stall...between 19-2100 stall one part number for both the 400 and the 440 engine 1977 & up
        High stall...between 22-2400 stall one part number for both the 400 and the 440 engine 1977 & up
        Factory converter will have a decal on it telling you if it's a low stall or high stall

        Lockup 727: Low stall and high stall listed ONLY for 400 inch engine. Stall speeds about the same as non-lockup.
        Factory converter will have a decal on it telling you if it's a low stall or high stall.
        Hope this helps, and higher stall lockups are available in the after market.
         
      • Dave6T4

        Dave6T4 Well-Known Member

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        The input shaft on a lock-up tranny will be drilled for fluid feed to the converter's lock-up clutch. Also splines do not go all the way to the tip of the shaft. I think there is also different spline count on these as opposed to non lock-up to avoid accidentally getting wrong converter installed. The 2100-2400 stall converter is what 383 Road Runner came with and works well. Interestingly, Mopar never put high stall behind performance 440's from the factory, figuring they made enough torque that they didn't need it. Both of my 440 equipped Dodges now have the higher stall converter, and I like it with 3.23 gears.
         
      • Dave6T4

        Dave6T4 Well-Known Member

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        I used to run TQ on my '64 and my '67 R/T wagon, until parts got harder to find. I always tried to use TQ from truck motors, with less emission stuff.
         
      • transman

        transman Active Member

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        Nothing wrong with a TQ. There's a guy in Spokane WA. that makes then look like and run like new. Had a customer that had one done for his 71 Duster. Wasn't cheap to get restored but he said it was worth every penny.
         
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