Depending upon what you choose to do and what chassis you're putting the gearbox in, there are are several trannies you can use.
Ford pattern Borg-Warner T-5. This info comes from an AMC page:
"T-5 from a Mustang will fit any AMC engine if you get the bellhousing from SR-4 ('76-'81), T-4 ('82-'88) or T-5 ('83-'88), and the throw out arm and bearing, from the same bell. Also the front bearing retainer is needed, if you don't want to modify the Mustang part. Right clutch disc with the correct # of splines that also fits the pressure plate you're using, and the pilot bearing is also needed."
Jeep Wranger\Dodge Dakota 2WD AX15 5-speed. Out of the Jeep, get the version used behind the 4.0. Out of the Dakota, get the one from the 3.9L V6 (However, you'll still need the Jeep 4.0 bellhousing).
If using the Jeep AX15 4.0L bellhousing, you can also use:
88-92 R154 5-speed out of the Toyota Supra Turbo (Very tough and good gear ratio's)
03 and up GM Colorado\Canyon pickup 2WD MA5 5-speeds.
Greg
