Exhaust Headers for Chevrolet Corvette C4 (1992-1996) 5.7LHigh Flow Long Tube Exhaust Headers for 1992 1996 Chevrolet Corvette (LT1 LT4 C4) What it Does: Replaces the restrictive factory cast iron manifolds with mandrel bent stainless steel long tubes to optimize exhaust scavenging and significantly reduce backpressure on Gen II Small Block Chevy engines. The Stock Corvette Exhaust Bottleneck The factory C4 Corvette exhaust system utilizes heavy, cast iron manifolds designed primarily for manufacturing cost