[fauXGT]

I have C4 front and rear suspension and have 16x8s with 4.25 backspace to put under it when paint and assembly is done. Can't find my notes on what tire size to get to work with the speedo in the 700R4. Wasn't much of a side wall bump out. That doesn't help with your C5 front rotors, but steel 8s are real close to frame and rear fender. I've guessed on the front clearance from memory from mockup junkyard 15x7 wheels before disassembly. I ordered the wheels over a year ago after others had said that's about the biggest that will fit. I might have to downsize.

I'ts all a guessing game until the end.