I did my first a few years ago using the Carl Munroe book "Torqueflite A-727 Transmission Handbook" which is excellent and also includes racing mods if you are interested in that. I also got a lot of help from tranny guys here on the site. I had built some Ford trannies before, but wasn't sure about the torqueflites. Turns out they are pretty easy if you take your time. Major rule: keep things clean!