I used to use them a lot on Gbody's. You have to make sure to get '86 and later wheels, because the earlier ones have different offset just like the IROK wheels. If you car is lowered at all or if the suspension is sagging at all it would be best to trim the lip on the tip of the upper control arms in the front or they will get into the wheel on a hard bump etc.... I always ran 215/65-15 on the front, and 245/60-15 on the rear. If The 255/60-15 will fit in the rear, but like was already mentioned, it will rub sometimes on corners or bad bumps.
Matter of fact, I have a pic of this set up on my first Elky SS that I did. This was my first Gbody and it made me fall in love with all Gbody's. It had all new MOOG springs and suspension, and all the F41 bars and whatnot. Mild 350 engine, th350, 3.73 posi rear. And yes, it was a real SS. I did two more of the SS Elky's before switching to Malibu 2-door's.
