You've really got to check the tag...the numbers stamped in the case are not going to tell you the OD ratio.
If the original S10 truck was a 4 cylinder you can pretty much bet it was a .86...if it was a 2.8 or 4.3 V6 I'd bet a .72. A quick way of determining the ratio on the S10 NWC transmission is with the transmission in 5th gear, mark both the input (front) and output (rear) at 12:00. Turn the output shaft (rear) 1 full turn (360 degrees).....and watch the front (input) shaft......if it turns over less than 3/4 (270 degrees) of a turn it's a .72....if it turns more than 270 degrees...it's a .86.
This should help you ID your T5 if you don't have a tag.
I've been running some numbers...if it does turn out to be a .86 and you're running a 28" tall tire it might just be fine with the 3.08. The key is to remember that the stock 235 makes good power between 1700-2400 rpms and that's where you want to keep it. I use this calculator:
http://csgnetwork.com/multirpmcalc.html I use the bottom calculator as it is more accurate. I hope this helps.
Dave
