[Art]

Do you mean a T-5 overdrive transmission?

 

[Huskinhano]

There is a T4. But I think he's got a toploader. A T4 is similar to a T5 except it doesn't have OD. They were used from IIRC 1975 and up in Mustang II's with V6's and V8's. Not a very strong trans for a V8 Mustang II though. They were made by Borg Warner.

 

[pprince]

I think you mean the BW T10

They are plenty strong. They were put behind most of the big block cars in the early 60's but they do have a habit of going through blocker rings.