I'm gonna have to swap to a T56 at some point
The Magnum trans is a dream and the wide ratio has a nice tall 6th, with 4.10s I'm cruising the same rpm as I would with a 3650 and 3.73s. If you do go that route do NOT use a shifter gasket on it, RTV it. There have been a couple of us that used a gasket that had an issue with the shifter bolts loosening (gasket probably collapsed/compressed slightly over time with heat cycles etc..). You can NOT reach the front shifter bolts with the trans in the car (well, maaaaaybe it's possible but it would be a royal pita).