My 68 Bird was an original 4 speed car and I'm going back to that. I have a nice super t10 6 groove with 3.42 1st gear, I know they are the weakest of the st10s. I also have a nice t5 world class from a 88 iroc that has had a few upgrades. My engine is a stock 75 smog era 400, which isn't a big hp engine but still makes alot of torque. At this point I can go either way and I just wanted opinions on what you would do. Street driven only, no slicks. And I'm not sell either and looking all over again for something else. These things are getting scarce. Thanks guys.