Thanks for the info.
I'm running an 8" that I have no idea what it came out of. It looks like if I get rid of the leaf springs and go with a 4 link or something (ala street rod) I might be able to put a it wider tire in there. One friend suggested I buy the size tire I want, remove the rear end and put them in the wheel wells, and then measure the flange to flange width. What do you think of this idea?