Ring & Pinion/Differential Kit?

earleys94gt

Active Member
Aug 31, 2003
1,223
16
49
Ashley, Ohio
I was just looking on Jeg's at gear sets for the 'Stang. I am wanting to get some 373's and found this kit for about $500 and designed for 28 spline axles.
http://www.jegs.com/i/Ford+Racing/397/M-4204F288K1/10002/-1/980343|123523

My question is, if I only plan on finishing my H/C/I with an intake and some injectors & MAF, for about 275-300 rwhp; and the car may see the track 2-3 times a year. Would this kit, or something similar and cheaper, be an okay mod., or should I upgrade to a 31 spline differential and axles?
 
its not your HP level that will bust anything in your rear end its your TQ. It all depends on what your going to run for tires at the track. I had 28 splines but was planning on getting MT ET Streets and knowing they would grip much harder then the Nittos were I went and up graded to 31 splines to be on the safe side. If your running anything more sticky then Nittos then its 50/50, some guys last awhile w/ no issues w/ 28 splines, some guys snap them like tooth picks. Myself being an hr and 30 mins from home at the track I didnt want to chance it.

PS: If I were you I would not get that kit, the differential is what you already have in your car to begin with. If your going to do an entire kit like that then Id upgrade everything to 31 spline.
 
So should I just get the gears and any necessary hardware, install them, and enjoy them?

Yeah thats what I would do, if your not going to do any substantial track time and just run street tires or Nitto's then your fine w/ your 28's. An entire rear end upgrade is expensive, heres a simple run down of what I did.


Moser 31 spline axles- $235

FMS 31 Spline track lock limited slip Differential - $ 220.00

373 Gears- $150

Plus rear end oil, new speedo gear, friction modifier and labor for the install. So all and all it can get expensive and if your just looking to do minor track time for the summer then just the gears are fine as long as your not running slicks or some serious DR's and dumping the clutch at 5,000 RPMS. Plus if you ever do want to upgrade you wont have to do the gears.
 
Thanks Redline. Yeah, I run some Hankook street tires and may do some track visits 2-3 times a year.

I am hoping I can get one of the guys at work to install the gears on the side for less than what it would normally cost.

So, I'll just need my gears, oil/friction modifier, any hardware, and speedo gear.
Sounds good.
 
Thanks Redline. Yeah, I run some Hankook street tires and may do some track visits 2-3 times a year.

I am hoping I can get one of the guys at work to install the gears on the side for less than what it would normally cost.

So, I'll just need my gears, oil/friction modifier, any hardware, and speedo gear.
Sounds good.

Yup that should cover everything. Where are you planning on getting your gears from? www.buyfordracing.com has them for $149.00 for 3.73's
 
I bent a stock rear axel with nothing but 3.27 gears and Nitto 555 DRs being stupid with a civic at a stop light. After replacing the axel with a stock unit, right before I sold the car, I made aroudn 15 passes at Epping NH with full slicks and 4.10s and the stock rear end held up fine to 4500 rpm launches.

In my experience, you are playing with fire with the stock rear end and any kind of spirited launching.

Adam