HDR 66-74 CHVY/GMC TRK 2WD/4WD Flowtech headers are the perfect combination of performance and value. Flowtech long tube headers are precision engineered using mandrel bent tubing, formed collectors and 5/16" flanges with sealing rings for a leak-free seal. All mounting hardware and gaskets are included for a simple installation. This header is coated in a high heat resistant black paint for a stealthy appearance. Features: Fuel Economy From The Engine Leak Test For Max Performance Mandrel-Formed Power Plenum Leakproof O-Ringed Port Seals Include All Mounting Hardware Construced of .049 cold roll flash mild steel tubing Precision engineered for fit, performance and economy Works with factory power steering and power brakes Application 1969 - 1974 Chevrolet Blazer 1966 - 1974 Chevrolet C10 Pickup 1973 - 1974 Chevrolet C10 Suburban 1966 - 1974 Chevrolet C20 Pickup 1973 - 1974 Chevrolet C20 Suburban 1966 - 1974 Chevrolet C30 Pickup 1966 - 1974 Chevrolet K10 Pickup 1973 - 1974 Chevrolet K10 Suburban 1966 - 1974 Chevrolet K20 Pickup 1973 - 1974 Chevrolet K20 Suburban 1968 - 1974 Chevrolet K30 Pickup 1966 Chevrolet Suburban 1967 - 1974 GMC C1500 Pickup 1973 - 1974 GMC C1500 Suburban 1967 - 1974 GMC C2500 Pickup 1973 - 1974 GMC C2500 Suburban 1967 - 1974 GMC C3500 Pickup 1970 - 1974 GMC Jimmy 1967 - 1974 GMC K1500 Pickup 1973 - 1974 GMC K1500 Suburban 1967 - 1974 GMC K2500 Pickup 1973 - 1974 GMC K2500 Suburban 1968 - 1974 GMC K3500 Pickup Specs Brand Flowtech Collector Diameter 3.00 inch Emission Code 4 Engine Chevrolet Small Block Header Finish Black Paint Header Flange Thickness (in) 5/16 inch Header Style Long Tube Primary Tube Dia. 1-1/2 inch Product Type Headers Tube Material Mild Steel Part Number 11500FLT