Now, this is what I found surfing around. Someone may certainly know something about the T-10 that I don't. But you may be much happier with a T-5 conversion, which will put a 5 speed trans in your 66. You certainly don't want an original Ford T-10, but you may want a Ford Toploader. For what a Toploader will cost you, you could do a T-5 for not much more. There are still deals to be had on Toploaders though, just harder to find these days.
Do some reading and post back.
Thanks a lot for the information. My impression is that the GT350's used the Ford toploader. I think I'll shoot for the real thing. Do you think that T-10's were used on 4-speed Mustangs in the '65, '66 era ?
Hipobuzz
Thanks a lot for the information. My impression is that the GT350's used the Ford toploader. I think I'll shoot for the real thing. Do you think that T-10's were used on 4-speed Mustangs in the '65, '66 era ?
Hipobuzz
The 65's and earlier used T-10's. I don't know that a current T-10 will bolt up to a Ford Bellhousing. You can still find the Ford T-10 occasionally. If you do, make sure you get the slip yoke for the drive shaft with it. It's got an odd-ball 25 spline output shaft, as do the early Toploaders
Thanks a lot for the information. My impression is that the GT350's used the Ford toploader. I think I'll shoot for the real thing. Do you think that T-10's were used on 4-speed Mustangs in the '65, '66 era ?
Hipobuzz
Toploaders were introduced on the Mustang in 1965 (although the 25 spline units used in 65 were NOT very strong--the toploader was strengthened the next model year). T-10s were most common in 1965 and early 66 but by mid-year 1966 the toploader would mostly replace the T-10. GM continued to used the Borg Warner T-10 for years.
Shelby, however, used the T-10, not the toploader for the 1965 GT-350. The T-10 was fitted with an aluminum tailhousing and was relatively light. Obviously it handled a decent amount of power, too. By 1966, the Shelby would come with the toploader if you ordered a 4 speed.
My A code 1966 Mustang (San Jose built November/December 65) came with a T10, which I have since replaced with a T5z. The T10 served its purpose well--very smooth shifts and was still going strong after 1 rebuild (with updated synchros) and 400,000 miles when I pulled it. Fuel mileage and long trips trumped originallity for me, though, or I would have kept it.
My advice: If you are adding a stick shift go directly to a T5 or a Tremec 3650. The overdrive will continue paying for itself as fuel prices rise even higher. I can pull mid-20s now on the highway, even with an old school 4100 4 barrel carburetor and Stealth intake and testosterone-influenced speeds. Unless you have a hyperkinetic build on your small block, the T5 will last a long time and can look quite stock to casual observers, especially if you keep your 4 speed shift ball and use a repro t-handle.
The T-10 was not a very good transmission. Boat anchors is what they were called back then. If you are going with a manual bite the bullet with and go with a T-5. You won't regret it.