Something to kick around.....the 89 and up T5's with the electronic speedo might not be such a bad choice for adding to a 235. Granted, the little "Cable X" box at $300.00 is a bit pricey but.....you get to use your stock gauge package and the converter box has switches that let you calibrate your speedo without changing the driven gear in the transmission. It took me some time on my back to get the right ratio for accuracy.
Secondly, the later model transmissions are going to have the potential for less mileage. The cost for rebuilding a high-mileage early mechanical speedo T5, will be appreciably more than the cable X converter box. If your stock gauge package is going to require extensive renovation, you might be dollars ahead to go with a later model, lower mileage electronic speedo T5 and the electronic gauge package. Same goes for the diff mods....I've located a 3.73 2002 Camaro diff which is supposed to be 62" wide with discs from a front-end wreck for $100.00 and all the coil spring hardware has been removed.
However, I would do some research and find out if and when the bolt pattern changed to insure your later model T5 will bolt up to your 235 bellhousing. Somebody might be able to shed some more light on this.
Dave
