The '99-'04 8.8" rear end has longer tubes as well as longer axles. So the short answer is, "No".

--Vince

 

Being that the difference is about .75" (30.688 for the 99-04; 29.969 for the 94-98), would it be unheard of to run a bolt-on 3/4" spacer if longer wheelstuds were used?

 

That would work, but I doubt the guy trading his IRS would want to run spacers.

--Vince

 

The difference is the 99-04 housing is physically wider by 1.5" than an 86-98 housing. That's the actual housing, not the brakes.

So compared to an 94-98 axle, the 99-04 axle is 1.5" wider due to the wider body of the 99-04 cars. Also, i beleive the LCA and UCA bolt holes are a different diameter than the 94-98 years.

If i was a Cobra owner, i would be specific in wanting an 99-04 axle as well.

 

Thanks guys. The car is a 2001 GT that has been converted to the IRS. Perhaps he will be cool with using a spacer, or finding a set of wheels with the correct offset to fit right.

 

I would be more concerned with the bolt holes for the control arms more than actual width.

 

Bringing this back from the dead to ask a question myself. I'm wanting to use my 94 8.8 rear end in my 99 V6 car. What problems will I run into when I go to install the older rear end? I have control arms for both cars (though I'd love to be able to use my Mac control arms from the 94).

 

You won't have any problems, the wheels will sit more recessed then if you used a 99-04 axle. I've done this swap into an 04 Cobra using an axle from a 97 car, it works perfectly fine. The bolt holes are different sizes for the LCA's (I believe the 99-4 use 12mm bolts, possibly 14mm I don't remember for sure.)