mgmuscari

So I've been doing a lot of reading here and there about gears, and I've decided to throw some 3.73's at my '89 GT 5-Speed. Right now I've got stock 2.73's and a T-5. I'm planning to go to a TKO-500 or TKO-600 in the future, and will probably keep this car naturally aspirated, unless I build a new engine for it.

Anyway, I'm wondering what all the parts I need to scrounge up are... I've heard that the FRPP gears and clutch packs are good... what else do I need? I know a fairly good mechanic in my area, but he tends to overcharge on parts so I'd like to bring everything with me. At this point I've decided that since I'm in grad school and this is my DD, I don't want to screw with installing the stuff myself (not to mention I don't have nearly enough tools laying around...)

Also, if there are any members in the NYC metropolitan area who know a shop that can do a really good job on mustang gear installs, please let me know - the guy I'm planning to get to do it is a talented mechanic, but I don't know if he's done a lot of rear ends and I can't afford to end up with a crappy install.

Mattalicious

If you're going to stay naturally aspirated, I highly suggest 4.10's. I just installed mine yesterday and am having a blast. Then again, to each his/her own.
As for what else you need..just a bearing set and some Lubricant(Royal Purple gear-lube works wonders).
My .02.

mgmuscari

I was thinking about 4.10's, but from what I hear it might be a bit unmanageable as a DD then... I live near NYC and will be driving this through the winter. I don't want to be losing traction everywhere. Right now I've got some Dunlop Direzza Z-1 Sports on it, 245F/255R, and am looking into picking up some snows for the winter.

Does anybody else want to chime in on the oh-so-tired 3.73 vs. 4.10 debate? I hear that 3.73's will really wake it up, but am I going to regret not going to 4.10's later on?

marcus33

i myself went with 3.73 mainly because i am a DD also. I travel from college to school to home all day and i was told 4.10 put u in a higher gear throughout driving so stop and go situations are a pain while hacing to shift 4 times then back off at the redlight then go back up. I am very impressed with the first and second gear improvment of the 3.73 and i dont think u'll need 4.10 unless ur gonan do some major work. For the snow- i have no idea. i would belive 3.73 would be better due to less torque in the first gears but i believe it dependent upon the driver. I hate driving my stang up hills when its raining and have never driven it in snow.

FivePointOhh

3.73's on a 5speed will be plenty for you. driving in the winter though will be increasingly more difficult with more gear.

Black89LX

here's what i did, go to latemodelrestoration.com and they have an install kit... thats where i went to get my 4.10's. gears alone are $150, the install kit that includes yukon 3.73's is $200, id suggest FRPP though... its 60 bucks more... then i went with the carbon discs for the trac lok, thats another $110... and dont forget the speedo gear, for like 10 bucks. im guessing its an 89 mustang, at least thats what it says under your sn... anyway, a 5 spd needs a 21 tooth gear, and an AOD needs a 23 tooth gear... all ive heard about the 373 vs 410 is that if you have an AOD, 4.10 is the way to go, i couldnt be happier with mine... for 5 spd, 3.73 otherwise first gear will take 30 seconds til redline, which flies right thru your power band...

hope this helps, but do some more research incase i made a mistake somewhere

Skyler5.0

410s will be fine in that car. I have a aod 3200 stall 410s and i drive it everywhere. All the time, no issues. My 87 and 84 gt's both have 410s an they are 5spds both ar N/A cars

Bubba 95SN

Go to 3:73 gears, for accurate speedometer display change the gear on mainshaft of transmission also.

Skyler5.0

here you go


5 Speed | 1983-89 | 1990-93 | 1994-98
Ratio/Tran. gear
3.27/ **** 19t **|** 21t **|** 21t
3.55/ **** 20t **|** 23t **|** 23t
3.73/ **** 21t **|** 23t **|** 23t
4.10/ **** 23t **|** 23t **|** 23t

Auto | 1983-1998
Ratio/Tran. gear
3.27/ **** 19t automatic
3.55/ **** 20t automatic
3.73/ **** 21t automatic
4.10/ **** 23t automatic