from
http://www.thepontiactransampage.com/transgears.html
Ford Mustang 5.0l 5-spd manual1986-1988
3.35, 1.93, 1.29, 1.00, 0.68
1989-1994 5-spd manual
3.35, 1.99, 1.33, 1.00, 0.68
Borg Warner Close Ratio T-5
2.95, 1.94, 1.34, 1.00, 0.63 (0.80 optional)
Tremec 5-spd manual (aftermarket)
3.27, 1.98, 1.34, 1.00, 0.68 Model: 3550
3.18, 2.06, 1.39, 1.00, 0.65 Model: 3750S
A lot of guys say a 3.73 makes first gear useless but that depends a lot on what first gear you have. For example:
3.73 rear gear x 3.35 first gear(stock stang)=12.496engine revolution to tire revolution
3.73 rear gear x 3.27 first gear(Tremic 3550)=12.197engine revolution to tire revolution
3.73 rear gear x 2.95 first gear(World class T-5)=11.004engine revolution to tire revolution
This is what I have on my Hunter Cobra and I love the first gear. I used to run a 2.73 rear gear and it sucked
2.73 rear gear x 2.95 first gear(World class T-5)=8.054engine revolution to tire revolution
with the Tremic to get a simialr ratio use a 3.55 rear gear
3.55 rear gear x 3.27 first gear(tremic)=11.609engine revolution to tire revolution
using a 3.27 rear gear
3.27 rear gear x 3.27 first gear(tremic)=10.692engine revolution to tire revolution
before I changed out my 2.73 gears first gear felt like you were starting in second and it is actually almost the same as my second gear is now. The overdrive was useless and any legal speeds and 4th was useless unless you were on the highway. This is even with 275/40/17 tires which are much shorter than the 275-60-15 a lot of guys run on FFR's and other Cobras.
food for thought