NEW AND IMPROVED "X2" CYLINDER HEAD IS MANUFACTURED FROM ALL-NEW TOOLING, MACHINED, AND ASSEMBLED WITH PREMIUM HARDWARE. THIS PROVIDES A FAST, EASY WAY TO BOLT ON SIGNIFICANT HORSEPOWER TO YOUR STREET CRUISER PACKAGE! High quality original equipment style 356-T6 aluminum castings, precision machined, and assembled with premium components. Includes Ford Performance M-6507-J302 intake valves, M-6505-G302 exhaust valves, and PAC(R) 1219X Ovate Beehive valve springs. Features wider valve cover gasket sealing rail to prevent leaks. Machined for gasket seat spark plug. Compatible with all Ford Performance roller camshafts and aftermarket hydraulic roller camshafts up to .600" lift. Work with many aftermarket intake manifolds, headers, and valve train components. Compatible with bolt down rockers 1.6-1.7 ratio, always check rocker arm clearance to valve springs with production rocker arms. Depending on lifter preload, Ford Performance Rocker Shim Kits M-6529-A302 or M-6529-B302 may be required. Each aluminum head weighs approximately 25 lbs. lighter than each production cast iron head. Each head is leak tested prior to assembly .