17104-Header-back System Dual Rear Exit American Thunder Moderate Sound Fits 1967 to 1974 Chevrolet Camaro and Pontiac Firebird, also 1968 to 1974 Chevrolet Nova, with V8 engines, does not fit convertibles without an X-brace modification, call Tech Support Line for assistance.
Note 1: Convertible models require an aftermarket X-brace or 3/8 shims for clearance