Hooker Super Competition Shorty Header96 98 Chevy GMC 4WD 2500 3500 pickups (including crew cabs & Suburbans): 396 502 Tube Size 1. 75" O. D., Collector Size 3" O. D., Collector Length 3", Port Shape: Same As Port; C. A. R. B. EO #D 164 5 ** Breaking in an engine with ceramic coated headers WILL result in damage to the coating and will VOID all warranties. Hooker recommends using cast iron exhaust manifolds or old headers during your engine break in period to avoid damaging your coated