maxshuty

Title sys it all

bigstick

Looking past the title, and seeing by your signature that your car is an '07.

I believe it's 3.31.

If you have a manual transmission, the 3.55 was an optional upgrade.

maxshuty

For an 8.8 it's 3:31? I'm asking because te salvage yard has one. It the guy said his computer didn't say weather it was gt or v6 an the only thing he knew is it was I good condition and has 3:31 ratio

Diabolical!

The 8.8 rear end from a manual transmission Mustang GT has come from Ford with either a 3.55 (standard in '05-'06 and optional after that), 3.31 (standard from '07-current) or 3.73 (optional since '10) gear ratio.

JimC

Max - there should be a label on the differential cover that has the gear ratio on it (I think it is the cover anyway and not the housing, can't remember for sure now).

And of course you know that if it is from a V6 from 2005-2010 then it is a 7.5" rear end and not the 8.8"

JIM5.0

Confirmed: as all above have said, from the factory, the 8.8in rear end housing was nominally meant to enclose 3.31:1 rear gears on sticks (manuals).
I do not know what the 2005-2010 automatic GTs were nominally supposed to get.

Also, as already said, you can get 8.8in from the factories with 3.55:1 & 3.73:1 rear gears as options.

On 2011+ GT, the 8.8in rear housings are nominally stock with 3.31:1 for stick with 3.55:1 & 3.73:1 optional.
The 2011+ GT automatics 8.8in rear housings nominally came with 3.15:1 because the 6R80 has a much deeper 1st gear ratio. 3.31:1 & 3.55:1 are considered optional in automatics, but I do not know if you can get 3.73:1 in automatics as an option.