'67-'69 Camaro/Firebird & '68-'74 Nova headers designed to work specifically in Speed Tech Performance Sub frame with Unisteers rack and pinion . Will not work with a steering box. 2" .065 wall thickness, CNC mandrel bent primary tubes. CNC laser cut flanges, 3 1/2" slip fit connector . These headers fit perfectly without dimpling the primary tubes around the steering shaft . Long tube design provides awesome low end torque and street performance while giving you incredible ground clearance. Sold less gaskets and fasteners. Mill finish. Will work with straight or angle plug heads. Will not work with factory A/C. These are the best fitting header and the only headers designed specifically for 68-74 Novas with our sub frame or your stock sub frame. Designed specificaly to work around a 2 joint one shaft steering kit for all Unisteer rack and pinion conversions. Made exclusively for Speed Tech Performance