You will like the T5, but you must have an open driveshaft and you must be very careful to study what gear ratios you have (in both the transmission and the rear end). Simple oversight can create something which is not nice to drive. As Evan said, nothing about this will be cheap and you must know where the shifter will be located. A 4 speed will cost as much as a T5, plus you will not get the advantage of an overdrive gear and you also must have an open driveshaft. In fact, with the 292, I can not think of any transmission which will not require you to change to an open driveshaft. You must also consider the cost to change to your emergency brake system, your regular braking system, spring mounts, pinion angle, shock absorber mounts, you may have to have a driveshaft custom made for you, etc. And your original mechanical speedometer may not work correctly with a different transmission.
Good luck. Personally I would say the least expensive option would be to replace the 235 with another 235.
