[Smurf stang]

I was curious to find out what or when is it time to upgrade the rearend? I know the 8.8 can be built up but when should you upgrade to 31 spline rear before it goes kablewie!!! My gears have been whining for some time since I bought the car.

[milford]

those rear ends are pretty tough.....the whining is because of to much clearance and could be because the crush sleeve is worn out,you could have another set-up done, a new sleeve and gear oil (of your choice),as long as youve had no trouble with the possi unit and youd be fine.....of course depending how much HP,and abuse....

[spdjnky_42]

31 spline w/ c clip elims is a def must if you have mods.

[Smurf stang]

In the process of swapping H/C/I and maybe just maybe a 100 shot.

[First5.0]

The rear ends are tanks. I know several mustangs with stock 28 splines and just spools and putting down 400-600 rwhp on slicks. Tanks i say!

[spdjnky_42]

Originally Posted by First5.0

The rear ends are tanks. I know several mustangs with stock 28 splines and just spools and putting down 400-600 rwhp on slicks. Tanks i say!

Yikes I would hate to ride in one of those!

[need4spd90]

Originally Posted by First5.0

The rear ends are tanks. I know several mustangs with stock 28 splines and just spools and putting down 400-600 rwhp on slicks. Tanks i say!

my father in law has roughly 280-300rwhp with a stock axled 8.8 from an 87GT in his FFR Cobra kit car

launching at 3500rpms on 235/60-15 MT drag radials with a minimal burnout..

snapped an axle right in half..

upgrade now.

[RLG34750]

if the rear is ready for a re-build that would be the time to upgrade to a 31 spline setup if your budget allows it

If not i would upgrade to a set of 28 spline strange axles.....

the 8.8 rear is extremely strong but the stock axle are not....

I snapped one putting the car on the trailer......

[EagleAutosports]

The material the stock axles are made of isn't the best. They are tough though, the time to upgrade would be if you're going to be hitting the tires hard with slicks and a clutch drop.
The 8.8 can be made nearly as tough as a 9 inch with the right parts. C clip eliminators, 31 spline axles, 31 spline limited slip center (posi is a Chevy term), rear end girdle that preloads the axle supports, and making sure the axle tubes are welded to the center will make it more than strong enough.

[Smurf stang]

Yeah I spoke with Pro Motion and having them build me up a sheet to see what it is going to cost me. As for the limited slip what do you guys think of the Eaton? It's like a $200 upgrade.

[RLG34750]

Eaton or Auburn great choice either one.....