what 4 speed auto transmissions can i use? 46rh etc

67Dart273 said
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What I'm saying is, "according to." If someone has actually DONE this with a 518 and not had to hack up the floor I'd sure like to see it.

I installed a 518 in my '73 Dart.
I removed the top of the crossmember entirely at first, and after a few weeks I fully welded the remaining part of the crossmember to the floorboards for rigidity as the spotwelds where starting to seperate.

Did not cut open the floorboard but used a healthy sized hammer to remodel/clearance the tunnel. The problem area is the ridge/nubs where the OD-unit starts.

I don't have any good pics of the modified tunnel because at the time of the installation it was a long day in the garage, taking pics was not high on my todo list.
This is the only pic I made during the 4 or 5 times I've had the transmission trial fitted up there;