The Stovebolt Site Forums The Shop Area Driveline T5 over drive gears

I'll chime in here briefly and then follow up later with a diagram and pics.
MOST of the V8 Camaro T5s from 1986-1992 will have a 0.63 OD gear. That's a pretty tall gear but will work well if you have plenty of HP. I tried one in my 1965 C10 with an L6. It worked but 5th gear would lug the engine on hills and I found myself shifting down to 4th gear.

So . . . . . I understand why people prefer the 0.72 OD gear. The 0.72 OD gear is usually found in the V6 Camaro T5s and most of the V6 S10 T5s. If you find an early V8 Camaro T5 with a nice 0.72 OD gear, GRAB IT. The 0.72 is the PERFECT OD gear for a 3.73 or 3.90 rear axle. That's the gear combo I have and I love it.

Here's the problem. You can't just remove an OD gear set from one T5 and stick it in another T5. (Well, yes you can but it may not get you what you want.)
Example: If you replace the V8 Camaro 0.63 fifth gear set with a 0.72 fifth gear set from an S10, YOU WILL NOT END UP WITH a 0.72 OD in the Camaro T5.
Here's why. The V8 Camaro T5 has 24 gear teeth on the input shaft and the S10 T5 has 21 teeth. Those numbers all factor in to the math for the final gear ratio FOR EVERY GEAR in that T5. I'll post a diagram later showing how the math works.

The earlier V8 Camaro T5s are NWC (1983-1987) and are the only V8 Camaro T5s that I have run across with a 0.72 OD gear and a nice 2.95 first gear.
If you find a 1993 or earlier S10 T5 from a V6 truck, then those usually have a 3.75 first gear (some have 4.03) and a 0.72 OD gear. Those are very good too even though first gear is a little low.