Ray, It uses the R10. They were used by Studebaker behind the V8s at least up to the 259 and I think the 289. Some of the 289s used the T85 R11s and T10 four speeds. The T86s are reasonably strong if not abused. My son went through 3 with the supercharged bored 289. One was low gear when he tried to make up lost traction on our boulder by applying more throttle. The other two were in second gear under hard acceleration and max boost just before shifting into 3rd. T86s don't have straight cut gears in low like some others did.
I have not even though about looking to see if the R11 might be adaptable to a T86. But we've never blown an OD. Probably won't the Stude has a T5 now.
