Putting 270 ft lbs in the back, stick with stock tranny?

[Daggis]

My sugestion would be to go with a 091 or 002 bus tranny.
They are only 4 speed, but with that kind of torque you don't need 5 gears anyways.

With either of these transmissions you can up it to 22psi and abuse it as much as you want to.