steve_kibbe,
I did this swap, from a TH400 to a SM465 in my 1973 Blazer. Here is what I did at a high level.
1) Get tranny, flex plate, shift fork, adapter, clutch plate, etc...
2) There is a big bracket under the steering column which you can either
a) add a clutch pedal too (I am pretty sure I have an extra clutch pedal)
b) replace with a bracket that has a clutch pedal
3) make a decision on Hydro or linkage. I have linkage and have had it pop out twice, but know how to fix it, just need to drill a hole and add a spring. Anyway, based on this decision, you will need the rod that goes through the floor, Z-bar, and bracket, or master and slave cyclinders.
Let me know wher eyou are int eh process and I will share as much of what I did as you want to know, down to part numbers and pictures if you want/need them.