Help with rearend and tires

I plan to use my 66 barracuda at the track. I am looking at a ford 9 inch for the back. I have a 440/ 500hp, and a 727 tranny. Can anyone help me figure out the flange to flange width of the ford and what tire size I will need. 51.4 is the normal f to f on a a-body 8.75, right? But to make room for slicks, Im not sure how to figure out a close starting point. I guess at this point I could use a little experienced assistance. I will tub it natch. Thanks. I have a chance to snatch a 52" f to f on ebay If I hear back from somebody within the hour, thanks much guys.