Quoting pauleyman:
90 does not have the biggest gearsets. What are you trying to do? 90-92 3/4 are different than 93 up. 90 intermediate and 1/2 are 90 only and cannot get a double synchro without custom machining. 90 intermediate has a smaller diameter. The shift rails and shifter are all different too.
I'm trying to keep my car running for more then 6,000 miles at a time. I've sheared the teeth of 3rd gear and 4th gear on two different occasions. So I guess 3rd went out in 6,000 miles and just 3rd was replaced, and another 6,000 miles or so 4th gear met the same fate, so 12,000 miles out of 4th. And it's a hd gearset in there. I dont baby the car, but I don't drive floor it from light to light either, so I'm just hoping I can get a tranny in there that will last me more then a couple oil changes. I don't know much about tranys or how the internals vary/work from year to year, but was told to get a 90 22 spline because they have the biggest shafts and have a bigger surface area on the gear teeth. Is this not correct?
Other option would be swap to an auto, or dogbox, neither of which I really want to do.