Here is how to make a bracket to use that trans in an A-Body. Its under construction right now, so if it doesn't load, try it later:
http://www.bigblockdart.com/techpages/abconv.shtml
It can be done, just need a bracket made. Here is a link with the bracket and demensions to make it. Good luck
http://www.bigblockdart.com/techpages/abconv.shtml