View Full Version : 3.55 gears in an 89 SC 5spd, is it too much gear?

05-06-2003, 01:41 AM
I have a line on a set of 3.55 gears for my 89 SC. I think the ratio from the factory is a pathetic 2.73:1, talk about cruising gears!! Anyway, I know for a 5.0 Stang, 3.55's were just about the way to do, 3.73's for the auto. My SC is a stick, and I just want to know if they may be too much? I like quick off the line, not high speed. I do most of my driving locally and not on the highway. Also, Which speedo gear would I have to get?


Phil Stocker

05-06-2003, 02:33 AM
Well I have 3.73's in two of my MN12's (autos) and I am very happy with them. I can't tell you what they'd be like in a 5-speed. As far as the speedo gear goes, use this:

Speedo Gear Calculator (http://www.sccoa.com/faq/speedgr.html)

and this to calculate your tire diameter:

Tire Height Calculator (http://www.sccoa.com/faq/tirecalc.php)


Kevin Varnes
05-06-2003, 02:37 AM
This seems to be more an issue of preference. Some think 2.73's are perfect, others think the 3.73's are just right. In my opinion, 3.27's are about the max that I would want to go on an early 5 speed SC. Our trans has a shorter first gear than the Mustang T-5 which would explain why they might run a numerically higher rear gear ratio and still be okay. I would stick with 3.27's. Much higher numerically than that and first gear becomes kind of useless.

j rick kirby
05-06-2003, 10:16 AM
mine is an 89 5 spd.I have 327's.perfect except 1st gear could be a little taller.I think I'm quicker 0-60 starting in 2nd and slipping the clutch and not having to shift this balky Mazda trans.

05-17-2003, 11:33 AM
i tried 3.55s in with a 89/93 trans and first is too low - you run out of gear too fast (ratios are like a wide ratio top loader). i would not go more than 3.27s. i use a 94/95 trans in my 91 sc and 3.55s work great (3.73 would probably be ok too but speedo gears may be a issue) because the 94/95 trans is more like a close ratio top loader.