You could always put a mustang T-5 tranny in it. That would hold any amount of horsepower you can make, and shift nice too. Also many aftermarket parts are available, and they are easy to work on.

http://forums.turbobricks.com/showthread.php?t=3620

http://www.v-performance.com/products.html

That should be all the info you need.

I've always heard that the M46 is strong enough to put up with just about anything you can hook to it. I certainly haven't seen too many failures of these, and the ones that did get damaged were due to oil leaks, not excess torque. Well, one kid broke reverse doing burnouts in high school... but that's avoidable.

Reportedly the M47, the true 5-speed trans in the 87+ cars, is a bit less sturdy. I wouldn't put one of those behind a built engine.

The M46 ought to be able to take anything your engine can dish out. A synthetic gear lube is probably recommended, like Redline MTL.

The few 740T's that were manual-equipped always used this transmission, as well as the 240T's. Note that depsite being the same gearbox, the 740T application uses a much longer shifter- you still need a 240 shift linkage.

Turbobricks.com has lots more info on how people are getting driveline components to survive behind their monster motors.
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Rob Bareiss, New London CT ::: '87 244DL/M47- 234K, '82 245T/M46-182K, '89 244DL/AW70- 212K Not too distant past: 86 244DL 215K, 87 244DL 239K, 88 744GLE 233K, 88 244GL 147K, 91 244 183K

hi there. i read over on turbobricks website above 250hp they use toyota supra tranny and rear end. there are adapter kits avalible. most 740 and 240 trannys are the same or close and wont do 250hp for the long run, as i understand it.