I run the AFS 17x9 Cobra wheels on my 85 w/ 92 spindles and an 8.8 (which should put me nearly identical to your setup, if you're talking about the 84 and have upgraded to 87+ suspension). I also have Eibach springs (about 1.5 lower, all around). I have one set of wheels for my racing tires (Michelin Pilot Cup Sports) and one set for the street tires (Eagle GS-1s). Even though the wheel offsets are the same and the tires are ostensibly the same size (255/40s), when you stack the two sets up side by side, the racing tires are a total of 1.2 inches taller (.3 inches per tire taller) than the street tires. The street tires clear at full lock, but the racing tires do not. The rear fenderwells, wheelwells, shocks, brakes, etc. are clear. Up front it appears to be the subframe rails / inner fenderwells making contact. I know this doesn't cover the 275 question, but for the Eagle street tires and Michelin race tires, there's a dramatic difference in true measured width relative to the advertised width. So, as several others have pointed out, it depends on the tire. Good luck.