Kelly, you know all the guys with mustang Steve are running big tires and brakes. You might want to check his site and do a search there. I can’t comment on the 65/66 part of your question. But you know...I’ve got 17x7 245/45/17s on the 70. They are factory 04 Mach 1 rims with about 5.75 backspace. I run 1 inch spacer on front, and 3/4” on rear. No rubbing. I’ve got the drop, Moog 8534 (BB) coils in front, 5 leaf reverse eye in rear. no rub, but I have about 1-1.5 inches or gap between tires and fender. I dont have front tires tucked in the fenders like Steve and friends.