I have a 90 IROC with a T5 and a 91 RS LO3 with a T5 and it feels like the two trannys have different internal gearing. Did GM have two different types of T5's....one for the Z28/IROC and another for the RS'? Anyone know?

 

They had different gear ratios, not exactly different "types", just different numbers of teeth on the gears.

There's a little info of that sort on the tech data page on this site; look through there, you might find what you're looking for.

Generally the non-performance cars like the L03 cars and 6-cyl cars got wider gear ratios. The faster cars got closer-spaced ones.

 

That's what I thought. Thanks.

 

For gear ratio information based on year and model of T-5 that was put into the F-bodies see the following post.

https://www.thirdgen.org/techbb2/sho...hreadid=162853

I posted this information a while back but looks like it fell from the current thread posts and harder to find. Will also try and post the T-56 information that I have as well as the 5 speed info that was put into the early 4th-gen camaros when I get a chance. Hope this helps.