crossmember swap questions

[musbrad]

Howdy folks,

I recently purchased a 1972 blazer 4wd, going to do the evil 2wd swap and airride. A friend has a 77 crossmember with drop spindles etc, from what I've been told, there are no holes that match from the 4wd frame to the 77 crossmember, do any of you guys have the correct dimensions from specific points where I can make sure I'm putting the crossmember in the correct position? I have a SWB 2wd C10 frame, I'm assuming I can use that to check, but if any of you guys have the info handy, I'd surely appreciate it.

Also, do the blazers have a 2 piece driveshaft or single shaft?

Thanks in advance

Brad

ps i've used the search function, but no specific distances have been given.