I have 255/60-15's on some of my 66's. Again with 15x7 Buick mags, 4-3/8" backspace and stock rears. They can be a little close to the outer wheelwell, but plenty of room on the inside. I rolled the lip on my Special, those fit fine. On my red GS, the rear isn't perfectly centered, so one side might rub on rare occasions. With the GS wheel mouldings, it's more difficult to gain clearance. Use can see how I did it on my blue car in the pics posted earlier.... rolled the fender lip, trimmed the molding thinner but left the screw attachment points... they look like tabs. Those tabs are bent up a little to fit the rolled lip. I did this about 30 years ago before the price of moldings shot up! Bob had told me his '71 8.5 rear was 61" wide between wheel mounting surfaces, with drums. I can check my '66 this weekend. '65's supposedly have more room due to the fender flaring out instead of in like on the 66-67.
I do not know where the rear end came from on my car, the ad that got my attention before I bought my car said that the original 2.93 rear end was swapped out for a 3.23. I know my car doesn't have it's born with rear end, because the speedo doesn't even come close to the speed indicated on my phone's GPS speedometer app. But judging by the lack of cast iron "ears" at the centersection, it is an early ten bolt. I'm glad you brought up the rear end because I forgot that when I first tried to mount my new wheels to the rear end, because of the wheel's backspacing I had some interference the lower shock that required cutting off the ears on the lower shock mount and moving the mount location up. Please see the attached PICs. Thanks.
Then if you roll the fender lip and plan on keeping the factory wheel well moldings, you will need to notch the moldings to go around the rolled area. Please see the attached. The clearance you see between the wheel and fender lips are with the wheels and tires that came with my car when I bought it. They were 225/70-14s. The clearance that I mentioned in my first post is with the 255/60-15s that my car now wears in the rear. Life is good. Thanks.
Not yet Jim, My buddy Nick White has a 15 x 8 wheel only so I'm going to bolt that on and take some measurements. I will be going to wheel ventiques for the wheels. new 15 x 7 up front. Nick also has a 15 x 7 with a 235 so we will bolt that up front to check clearances. I'm ready for a first test drive but I have junk yard tires on it right now. soon enough though. thanks for the input. it did help.
