Header tubes are pre-polished for a better appearance Precision formed long transition collectors and long tube design reduces backpressure and increases higher RPM horsepower Tubes are pre-polished to removed scratches before applying metallic ceramic or hi-temp black coating Long tube headers provide the greatest increases in horsepower and torque across the entire RPM spectrum. The choice of racers worldwide, Doug's long tube headers are... Header development and design is complex and requires a substantial amount of time and resources to do the job right! Doug's Headers D200-B Doug s Headers D200-B 1 3/4 4-Tube Full Length 400 455 Exhaust Headers DOUG S HEADERS D304 Metallic Ceramic Coated Headers Instruction Manual 4 Tube Headers For Pontiac 400 Heavy gauge tubing (16 and 14G) for longer life Doug's Headers Headers, Long Tube, Steel, Silver Ceramic Coated, 2 in. Primary, 3.5 in. Collector, Pontiac, 400, 455, Pair See More Specifications CNC mandrel bent tubes for an accurate fit and a better flow Doug's headers are carefully developed on the vehicles they are intended to fit and are re-checked numerous times during the design and manufacturing process.
