72 lark convert upsizing my keystone klassics in rear from 14-15

[firered]

need some opinions about tire size. have 14x7 225 70 all around right now want to improve stance and lower rpm's on the highway want to upgrade rears to 15 the klassics have bs of 3.875 for 8" rims and 3.75 for 7"rims want about a 28 in tire to get about an 8% reduction in rpm's was thinking 275-60 or 245- 70 i dont think a 2 inch diff in height from the fronts will look too jacked up and should look nice a 29 in in the back would prob be pushing it

[Nothingface5384]

i believe you're going to need more backspace for the 8s to run those 275 60s

typicaly you;d want to go with a 4.5 bs with 15x8 and a 275-60-15 but 4.25 will work too...maybe 4in backspace..but might rub a tad

[pwm72]

I have 15x8 on my rear with 4.5"bs. I run BFG 275-60-15 and they fill the wheelwell nicely on my 72 convert. 28" tall and helps tame my 3.73's a bit.
http://i23.photobucket.com/albums/b352/pwm72/4.jpg