You measure for the correct drive shaft length. There is no gaurantee of a correct fit other wise as the length changes with the ride height (some people actually enjoy scraping over every speed bump in the road and make their cars lower than stock). If you don't know how to measure for a drive shaft Denny's Drive Shaft has a page that explains the procedure:
As to the rear yoke, it uses the same 27 spline out put shaft that the PowerGlide, the TH350, the manual three speed, and the manual four speed (both the Muncie and the Borg-Warner T-10) do. Only the TH400 and the new manual four and five speeds use the larger stronger 31 spline out put shaft and front yoke.
You have an aftermartket transmission cross-member so that will acount for the mount being moved to the rear (because of the extra fourth gear in the TH350 case that turns a TH350 into a 700R4) so that won't be an issue. All you need now is linkage to find those two extra gears (longer rods) and a gear selector plate to go in the dash (or on your console) so that you know what gear you are in. That assumes you want it to look stock. If your are going for the ProMod look you just bolt a ratcheting Hurst reverse lock out shifter on the floor and drill a hole for the cable to go through.
The last and most critical thing to do has to do with the TV adjustment. Get this wrong and you will be buying another 700R4 transmissin inside of a day or less. You need a sturdy (not cheap) mounting bracket to secure the cable. If you have a Rochester carburetor youi are in luck as there are literally millions of good stock ones in salvage yards waiting to be picked up. If you have a Holley or a Carter (aka Edelbrock) carburetor then you have to buy an expensive strong (you are standing on this part) bracket to keep the cable end where it needs to be.
A bracket is only half of the problem. The Holley or Edelbrock carb doesn't use a Chevrolet throttle arm. This is because Chevy didn't use a 700R4 with Holley, only a manual trans or a TH400; and because Chrysler (MOPAR) used Carter carbs as their stock carb (The Holley has Ford throttle arm because Ford sourced Holley as their OEM carb vendor). That means you have to modify the throttle arm to make it work with a 700R4.
Here is a web site or two that explain this issue.
This bracket only allows the throttle to bolt up but can be modified:
Here is someone talking about the brackets