8.8 or 7.5 in 86GT??
 

I'm getting ready to order the remainder of the necessary parts to install my 3.27 gears (it's got 2.73s now), and need a clear answer before I spend the $$. I've already got the gears.

Most articles I've read have stated that the 86GT was the first year the 8.8 was used. I've also heard/read a couple times that an 86GT owner swapped out their 7.5 for the 8.8.

I'd hate to get everything I need together, tear down my rear end only to find out it's a 7.5.

Can anyone give me a clear definite answer? I'm pretty sure it's the 8.8, but I have a small amount of lingering doubt.

Your right on there. 86+ Mustang V8's came with the 8.8" factory. Check out www.mustanggt.org, just to clarify it. Check your axle tag if it's still attached for the the rear end #. You can usually tell just by looking at it size wise, whether its a 7.5" or 8.8".

Easiest "rule of thumb" is that a 7.5 has a single bolt at 12:00 on the cover, an 8.8" has 2 bolts at 11:00 and 1:00

This should help you out.

http://www.nationwideparts.com/differentials.htm

Off the subject a bit, but can you post a picture of your in fullsize view? and is it t-tops?

Sorry, I don't have a fullsize pic at the moment. The car doesn't have t-tops.

After looking at the differential cover pattern, I found that my car does in fact have the 7.5.:confused: :mad:

Time to start looking for an 8.8.

7.5s
 

I thought '86s had 7.5 rearends. I guy I used to work with was building up his '86 GT and he too had to replace the 7.5 that came in it.

All I know is I have 2 mustangs and both have different size rearends, I measured and one is about 2 inches larger than the other, do they make a 6.5?

Heres a cut and paste from a website that sells rearends

"All 1979-85 Mustangs came equipped with 7.5" rear-ends (7.5" refers to the diameter of the ring gear). 7.5" rear-ends also came in all 1979-04 non-V8 equipped Mustangs. The stronger 8.8" rear-end debuted in 1986 and still rides under all V8 Mustangs to date"

I've looked at two 86's, both with V-8s and they have the same differential cover pattern. I've also looked at a 98 1/2 ton Ford Van, and it too has the same pattern as my car. According to pictures I've seen in MM&FF, the rear end in my car is an 8.8, according to a previous link on this subject, the rear end is a 7.5.

I'm cunfuzzed. :confused: :confused: