When I bought the car it had the original C-4 transmission in it. The trans drove fine and I put a shift kit in it, but it was never what I really wanted. For this car an automatic just wasn't the right option, especially when you throw in the fact that the auto had no overdrive (and I had 3.89 gears) and I could never get every last leak out of the 40+ year old transmission. I went through several stages with rectifying this situation:
Phase 1 — Part together everything for a T-5 swap. This lasted a while, but at the time I didn't have the funds to do what I really wanted, so I scrapped it.
Phase 2 — I purchased a good working AOD out of a fox body Mustang with the idea that at least I would have the overdrive and it wouldn't break the bank to get it fully functional. After doing some basic measurements of the beast of a transmission and looking at the rest of my setup I realized that the AOD would fit, but I would have to cut the headers at the collector, angle them differently, and have them re-welded. That and the entire back half of my exhaust was going to have to be custom built as well. This "budget option" was no longer in budget. Luckily when you buy used stuff you can usually get out from under it without losing money.
Phase 3 — Quite a few years down the road and in a better budget position, I got lucky and found a guy that wanted to sell a complete working T-5 setup still in the car for $600. It was in a 93 Mustang GT with incredibly low mileage (32K on a car that was over 20 years old). I got to drive it, then pull it and drive home with it that night. As a bonus it had a Lakewood bell housing (new in box), a B&M shifter, and an expensive 50oz flywheel and high performance clutch. After selling the Lakewood, flywheel, and clutch I was sitting with a good transmission and shifter for very little money. Parts needed for the swap:
