Yes, I know it's been brought up many many times over the years, and I just spent 2 hours using different search words trying to locate this info. This is not the first night I've spent hours researching this topic online. I finally have to give up and ask you all for help.

Therefore, if you could be patient with this question I would be much appreciative. '68 RR; looking to put 15" steelies all around (will purchase Wheel Vintiques through Summit I guess); most likely going diamond back redlines; I'm pretty set on going 275/60's in the rear but not sure if 4" or 4.5" back spacing is appropriate.

Front- undecided on 235/255 60's or go 225/235 70's. Also back spacing.

Thoughts and pictures would be great before I drop a lot of money (at least on my teacher's salary) on these. Thank you in advance!