You'll need a clutch spring compressor and an SBC cam bearing install tool. You might want to verify if that will be the right size for the output bushing at the back of the case. That works for the th350 but I can't remember if the OD cases are different. Shouldn't be, because they are both 27 spline outputs. You can make the clutch spring compressor from a lock plate compressor or a caliper spreader. You'll also need a bushing driver set, like the one at HF. The pilot bushing in the output shaft can be cut out carefully with a dremel, otherwise I think the tool is like $30 on Amazon.
Can't think of anything else specifically other than a couple good pairs of snap ring pliers and some feeler gauges. I take the bare case to my friends at the axle/****** shop and they spray it in their wash cabinet. That is worth every penny of a case of the ****** beer they drink Lol.
There is a th350 book by Ron Sessions that summit carries for $20. Don't know if there is something similar for the 700r4 / 4l60 / xl6xe trannies, but a lot of it would carry over since it is the predecessor to those. Either way, that book is worth $200, and I would want to have it if you are in to doing Turbo Hydromatics or any auto really. If nothing else, it goes over how to either make or work around most of the special tools any auto mech. will need such as using feeler gauges or piano wire to install orings and stuff.
Oh, you'll need a dial indicator to measure end play, and a caliper to measure shim thickness. Most of this stuff is stuff that any mechanic this stubborn is going to need for other stuff like engine overhauls, ring and pinions, etc. The only tool I specifically need for TH trannies is the clutch spring compressor, which I made from a caliper spreader in like 45 seconds (I posted a picture of it on this forum somewhere a few weeks ago).