I recently sent a '60 Apache carrier with a 3.90 ratio to ndkid275. He is in the process of swapping a T5 into his 3100. It is currently a 3 speed with a torque tube.
The '55-'60 carrier is a direct bolt in and allows you to use your original axle. You would still need to add perch mounts but at least you wouldn't need to worry about width or bolt pattern.
Send ndkid275 (Chris) a PM, he should be able to give you all the details.
