Your fitment issue is the tunnel you will need a BFH. What engine are you planning
I'm going with a 360. I have the original slant 6 for the Dart but i was wanting to put that in my 50 Hudson..still kind of deciding.
Gear ratio
5 speed nv-3500
4.01 1st---- 2.32 2ed----1.40 3ed----1.00 4th---- .73 5th
http://www.forabodiesonly.com/mopar/showthread.php?t=238690&highlight=speed
http://www.forabodiesonly.com/mopar/showthread.php?t=116056&highlight=speed
Not a nv3500 but
http://www.forabodiesonly.com/mopar/showthread.php?t=178459&highlight=speed