1998 - 2003 Corvette Convertible: Prevention of Convertible Top From Rubbing Against the Paint Behind the Plastic Strip
If you raise the rear portion of the canvas top, you will see the strut rods on each side which can be adjusted.
Each rod has a 13mm adjusting nut and a 15mm locking nut. Loosen this locking nut and slightly turn the adjusting nut a little at a time. Each time you turn the nut, raise the top and check for proper clearance. The amount of clearance should be equivalent to the thickness of a credit card.