HELP!North TX '69 GMC rear axle swap clarification

[tx69gmc]

Hi guys-

Can someone please clarify once and for all for me which donor rear ends I can use to swap into my 69 GMC SWB to get a 5 lug rear? Are they any that will work that are available with Posi? I am really wanting to do this swap but get quite a few different opinions out there I think that finding a donor truck would be the easiest and most economical. Correct me if I am wrong. Many thanks.............. Anybody in the North Texas area that has done this swap please speak up.