8.8 diff

cobra427mnsi · #1 (**permalink**) 04-19-2002, 01:21 PM

-This is a question to DV or Dscott-

Hi guys

I was reading in a previous thread that the newer mustang 8.8 has disc brakes. Is that true for all of them or are the disc brakes only on certain models and years of mustang. If so, which models and which years. I also remember reading that the newer 8.8 diff. is about 1 1/2" wider than the older one. The one I have is out of a 1990 model mustang. I would like to upgrade to disc brakes and go to 327 or 355 gears (presently 273 gears). I would also like to upgrade my wheels to Team III 9 1/2" X 17" on the rear. What backset should I order. Presently I have 8" X 15" wheels with the setback originally recommended by Classic in their built manual. My cobra is a 1992 model with 94" wheelbase. I assume the newer and wider 8.8 diff has the same mounting points as the older narrower diff.

Jack21 · #2 (**permalink**) 04-20-2002, 10:17 AM

Went through the same exercise, so I'll add $.02.

The drum brake Mustang 8.8's from about '83 to about '93 were the same width. The later disk brake rears were a little wider. Where the breakpoint occurred, I'm not sure.

My diff is an '84, and was recently rebuilt with 3.55's, 5 lug, and new posi by previous owner, so I just bolted it in the car.

The Ford SVO tech guys advised the M-2300-C rear disk brake conversion kit for '79 and up Mustangs, so that's what I got. This is the same brake setup that came on the '87 - '89 T-Bird Turbo Coupe. Comes with correct master cylinder for 4wdb (lines come out on engine side - easy install), e-brake cables, prop valve, etc.

Front brakes are Stainless Steel Brakes 4 piston calipers on 11" '75 - '80 Ford Grenada rotors. These are newly manufactured Kelsey-Hayes calipers that were OEM on '66 Mustang GT (and presumably the Shelby GT-350) So, the setup is all Ford, and the car does stop on a dime. My setup dialed in with the proportioning valve all the way open, but yours may not.

Using 17" Team III's. 17"x8" front backspacing set at 4", same as OEM 15x8. 17x9 1/2" set a tad inboard at 5". 4 3/4" would have worked OK too.

If I were doing this again, I'd change a few things.

Use the 31 spline, not 28 spline axles (beefier), and one of the newer, beefier posi units rather than the stock Ford unit.

The front rotors are 11", rears are 10". That's all you can fit on a 15" wheel car, but the 17's are a different story. Looks pretty miniscule inside these wheels. Shop around for 13" front, 12" rear rotor brakes. The FFR guys that use all late model stuff including 17" wheels use the bigger brakes. The question, how do you mount a late OEM 13" rotor and caliper on a Mustang II spindle? Baer, of course, will set you up for about $1000 (fronts).