Prepping A518 46RH for power upgrade

Transmission and Drivetrain Tech

  1. Stroked408

    Stroked408 FABO Gold Member FABO Gold Member

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    When I bought my 68 Dart back in January of this year I was happy that it already had a 518/46RH installed. That being said, once the 318 blew a head gasket back in March, I decided to upgrade to a 340 stroker motor that will most likely push 500 hp. The transmission was shifting great in and out of OD, downshifted fine, etc. But like the motor, I have no idea on how long ago it was built or how many miles are on it. Now with the motor and transmission out, I contacted John Cope at CRT and asked for some advice on what I would need to do if I'm pushing 500 hp and may occasionally take it to the strip. I went with the 518 race rebuild kit and the TransGO TFOD-HD2 shift kit. The converter I have is fairly new (Turbo Action Street S-800 3200-3500 stall). I'm still looking for a reputable transmission shop in the SF/Oakland/NorCal area that can do this for me, as I don't have the skills for this.

    There was a hand fabbed crossmember which held it in place but it looked weak so I bought one from CRT. Much sturdier and I don't have to weld in mount support like the US Car Tool crossmember. I have a column shift with the OD button at the end of the shifter handle. At some point I'd like to install a floor shifter, possible a Turbo Action Cheetah, but I don't know what brackets I'll need to connect it to the top of the trans.

    hf xmember 1.jpg

    hf xmember 2.jpg

    CRT xmember vs homebuilt.jpg

    CRT xmember mount.jpg

    CRT xmember fit.jpg

    CRT xmember on Dart.jpg
     
  2. rustycowll69

    rustycowll69 Well-Known Member

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    Wow, does it really have to hang that low? I don't care much for the way the new mount has those flat plate ears. I'd think if they were boxed in on the bottom, that would make it much more rigid.
     
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    • Stroked408

      Stroked408 FABO Gold Member FABO Gold Member

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      I see what you mean, that can be done once I check the fit of the 3" pipes next to the crossmember. Here's a shot of the old crossmember under the car, it didn't hang that low.

      dart underside.png
       
    • Mtrhead

      Mtrhead Ace of Spades ♠️

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      Strengthen the old one..
       
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      • Mopar44134

        Mopar44134 Well-Known Member

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        does the crt mount sit lower so you don't have to modify the tunnel for the 518?
         
      • Kendog 170

        Kendog 170 Let the boy go !

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        That new one may change your pinion angle ? Agree with Post#4
         
      • oldkimmer

        oldkimmer FABO Gold Member FABO Gold Member

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        It won’t change the pinion angle. It will change the trans angle. Kim
         
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