How strong is the 8.8" Ford rearend?

[N A]

I have the factory 8.8" Ford rearend with 3.08:1 gears and non-locking differential. I want to add 3.55:1 gears and a Traction-Lok, but should I upgrade the 28-spline axles to 31-spline axles and diff? The car will be used hard on the street and at the strip with slicks.

[Blaze86Vic]

Don't worry about it. Upgrade if you ever break an axle, which generally will take much greater than 400hp. If you do upgrade to 31 spline, you will have to swap the whole rear end anyways. The only factory 31 spline setups for our cars are on the limos.

Are you going to be drag, or street racing more? If you are going to be street racing I would recomend the Detroit TrueTrac that I have in my Vic.

[N A]

How do you like the Detriot Truetrac? Does it use 28 or 31-spline axles? I just don't want my rearend to break. I'm going to be using the GM more in the Spring.

[Blaze86Vic]

You can get 28 or 31 spline TrueTracs. The reason I suggest this is for road traction. If your racing is going to be pretty much strip only, then a clutch limited slip will work better for you. I love my TrueTrac. It's not a clutch type LSD, it torsion differential. It transfers power to the wheel with the traction instead of the other way around. This leads to the right amount of power going to each wheel, not just the same amount.

http://grandmarq.net/forum/viewtopic...troit+truetrac

[DuceAnAHalf]

http://www.moserengineering.com/mose...r/axletech.htm

31 spline axles are not needed until you are close to 600 ft/lbs at the rear wheels, and then as long as you are not doing 4000RPM drops at the strip on slicks you should be fine.

[HwyCruiser]

There's a lot of Marauders out there pushing 400+ rwtq and not having any problems with the axles, and many of them may still be running the soft axles and don't even know it. I've heard of only a couple of people have upgraded to the 31 splines as a "preventative" measure.

An axle housing girdle with bearing cap studs isn't a bad idea either if you're going all out to build a bullet-proof rear end.

[p71towny]

Yeah, no need to really upgrade these unless you have a monster engine.

[mrltd]

Uslydawg blew the carrier out of the cover....That was with a mild 5.0 (under 300HP). Nevermind that he was pulling the wheels launching.


I never had any problems with mine. And I beat the crap out of my car.