What is the largest 60 series tire that you can put on a 1990 IROC with a 15x7 wheel?

I was thinking of going 235/60/15 for the fronts and 255/60/15 for the rears, but now I'm getting kind of cocky and was wondering if a 265 or a 275 would fit on the rear without rubbing the wheel wells at all. I was thinking that it would give it a nice looking stance, along with some added traction.

Anyone have any pictures of their sizes for reference at all?

Thanks,
_Clark

 

I had 275/60/15's on the back of my 91 when I took it to the strip with the factory 245/50/16's on the front. The back stuck out bout an inch on each side and lifted the rear up a little.