The Stovebolt Site Forums The Shop Area Driveline T5 Drive / driven gears ?

Hello T5 fans.

I have a T5 from a 93 S10. I am switching out the tail section with one from a 1983 S10 , so I can use my original speedometer.

First I have an assumption based on reading previous posts on the T5 swap. The assumption is that I will need a longer speedometer cable, other than that it's a direct hook up. Am I understanding it correctly?


And some questions.

A 9 tooth drive gear and 18 tooth driven gear came with the housing. Based on my math I will need a 25 tooth driven gear. OR.. 7 tooth drive gear and a 19 tooth driven gear. Is that correct?

for the math I used
Tire (P225/75R15) 28.3 in diameter, 713 rotations per mile.
3.90 rear end

Second question : What is this in the photo. It came on the 1983 housing. From what I have been able to find its some type of reducer? How would it affect the math when determining what drive/driven gear combination.

these are the markings
663A. C9
.7333 AAC


As I understand it, I will not need it If I get the correct drive/driven gear combination.

Thanks for the assistance.