Since the 292 has the same bell housing bolt pattern as a Chevy V8, you'll have a pretty wide selection of transmissions, even some with an overdrive option. The SM-420 is an obvious choice, but there are also 5 and 6 speed medium duty truck units that would be more versatile. I think the T-5 would be a bit too flimsy for what you're trying to do, especially behind a high torque engine in a vehicle that's doing real truck stuff.
Jerry
