For those w/ C5 Z06 brakes & aftermarket wheels...

[kikaofazz]

What backspacing do I need to go with to make sure that the front wheels clear the calipers? I had to put my stock wheels back on (not sure of the backspacing), which just barely clear. Help's appreciated in advance!

[tapout]

All Grand Sport coupes used ZR-1-style five-spoke rims with 275-40ZR17 rubber on the front and 315/35ZR17 on the rear. With all this wide rubber on the car, GM had to find a way to make it legal by having it inside the wheelwells. Initially, the design team considered using the ZR-1 wide body for the GS, but reconsidered because they could upset the ZR-1 customer who paid a premium for the ZR-1 drivetrain and different body style. Then they decided to tuck some of the tread under the car by going to an offset wheel and using European flares already in the GM parts bin on the GS coupes. In fact, the Grand Sport wheels were the same as the '94-'95 ZR-1 five-spokes except they were painted with a glossy black finish and had the aforementioned 50mm offset rather than the ZR-1's 36mm.

from : http://www.corvettefever.com/feature...nvertible.html

I have these on my car. and i do have the ZO6 conversion.
36mm to answer your question.