Mild steel, 16-gauge tubes are CNC mandrel bent, then carefully welded on our precision engineered welding jig for a perfect fit. These fit both automatic and manual transmissions with the more common 157 Tooth small bell housing, along with extra clearance for starter, mounting flange bolts can easily be accessed and they clear shock towers. Provides full articulation of steering assembly without interference. Power steering cars require a drop-down bracket. Cars with the larger Bellhousing for 164 Tooth Flywheel will need to dimple the header and possibly remove a minimal amount of material from the bell housing for proper clearance. Shortened collector tubes improve floor pan clearance. All Headers include extra-thick, precision ground 5/16" inch flanges to prevent warping, metal composite flange gaskets, 1" inch primary tubes, 1" inch secondary tubes, and 2 1/2" to 2" inch collector/reducers. Gaskets and all necessary mounting hardware are included.