Gotta weigh in on this one. I ran a T5 behind my 350 for 2 years. The unit was out of an 87 Camaro with V6. I long ago outgrew my teen-age need for horsing around with my vehicles, so there was never any undue stress placed on the trans. My feeling was that it would last as long as the engine. I didn't like the gear ratios, and couldn't find one with what I wanted. There are dozens of T5s out there, and several websites devoted to them--mongos garage and british v8 are ones that come to mind. Each t5 has a tag number beginning with 1352- and followed by three more digits. These tag numbers are the key to what the trans came from, the ratios of every gear, etc. I removed the t5 and installed an MY6, aka 89mm, aka A833. The link to the CCT article is a good one. At first glance the 833 looks like a T-10, especially when you see the Hurst 4 speed shifter attached. I like it--20% less shifting, and still have my OD. I also think it is a direct bolt-in to your 55. Mine is in a 57 with 1970 engine. Good luck
