The rear upper control arm ball-joint cap interferes with 16" drag wheels on the C5/C5 Z06 and must be dimpled with a ball peen hammer. The picture above shows a C5/C5 Z06 ball-joint modified to fit a 16" wheel. Keep in mind you only have to dimple the cap of the of the ball-joint to fit our drag pack, not the bridges on it. Picture is for reference purposes only.