Something to be wary of on your rims, most modern rims will not fit the older mustangs. if you try for 16's you have to have them specially made. I ran into this problem recently, I am rebuilding a 66 mustang,doing a 6 cylinder conversion right now (straight 6 200 -> V-8 289) and I had to replace the rear end (4 lug bad 5 lug good on a V-8) All of the tire places in the area have told me I need to order my rims from the rim companies since the standard sizes don't fit the older mustang.
