International Scout HeadersOur headers use 1 5 8" primaries into 3" collectors. All tubing is 14 gauge steel . 083 thick. 3" Gasket less ball socket couplings are used. Flanges are 1 4" thick CNC Laser cut. The ports are hand finished and the face of the flange is machined flat. We weld completely around the primary tubes where other companies do not. Header gaskets and 3" female ball socket adapter are included