I just went thru this with my 69 notchback barracuda. I have an A-Body 8 3/4 rear (not sure what year car it came from as they do vary in width depending on the year from what I've read). But I went with a 15x8 with 4.5 backspacing with 275/60R15 Hankook tires in the rear. I ended up adding a 1/4" spacer so I have 1/2-9/16" space between the tire and leaf spring. Up front I still have stock drum brakes and went with a 15x6 with 4" backspacing and 205/70R15 Hankook tires. The tires were on the large side for the sizing and I didn't quite have the distance between the fender and tire like I thought I would so I rolled in the lower 2" of fender lip in to gain a little more clearance. Ended up with 1/2" which should be fine, but if I had to do over again I'd go with the 215/65R15 tires for the front.