Somewhere I have both a book on rebuilding a Turbo 350 and a rebuild kit. I've had the kit more than 15 years...
I can't claim any expertise and this is something I've not even tried before. Based on what I've read I do not think I'm afraid of a TH350 but a 700r4 would scare me. I've got a couple of TH350's around here and might someday actually do it.