Fred,
I haven't seen any 3:91 gears listed except in the Ford book for the 69 Cobras. Not sure if you could order them in the GTs or not. The 3:70/3:73 I don't know about as my rear end in the replica is an 8.8". And it has a 3:27 with a built up Eaton Posi Trac and 31 spline axles. I need to sell it as I don't ever drive it any more. In pretty good shape and cheap.
Ron
