hi guys.. i was wondering if i can get some do's and dont's with a frame swap..
and also if the 4 door frame is the same as the 2 door frame. on a 71-72 A-bodys

WELCOME to the BEST site on the web.

If you would do a search by clicking on the search link in the upper right side of the page, you will probably find more info than you thought imaginable and use frame swap as your keywords.

You can use a 4 door only if you want to shorten it 4 inches around where the rear passenger floor area is.
Here's a link;
http://www.angelfire.com/tx/lonestarclassics/chassis.html