Mind if I suggest a really good electric fan w/built in shroud like this: http://www.fordmuscle.com/archives/2003/02/electricfan/index.php I can tell you first hand that they move alot of air! *If you only wish to use the mechanical fan and can't find a good shroud at your local yard(s), let me know. There are a couple of v8 G-bodies here.
I've got an extra one, if you were closer you could come get it, but you shouldn't have a hard time finding one at a salvage yard. hence the extra one i have.