The Edelbrock Performer Street Legal Cylinder Heads offer improved performance throughout the RPM range for great throttle response and top-end horsepower with excellent low speed torque. These heads have the same powerful design and combustion chambers as the straight plug Performer RPM heads plus an exhaust crossover passage for emissions equipment compatibility. These aluminum heads are sold complete with 2. 02 intake valves and 1. 60 exhaust valves, pushrod guide plates, 3/8" screw in rocker studs, and larger than stock 1. 46" diameter Edelbrock Performer Series valve springs, locks and retainers. The springs are designed for cams up to . 575 maximum lift. They feature 70cc combustion chambers and are assembled and ready to use. They have threaded inserts in the rocker studs and exhaust manifold bolt holes for superior strength and durability. These 50-state street legal heads work with the Performer Power Package and provide outstanding street performance.