The Edelbrock 770468 Victor LS-R CNC cylinder head is ideal for use with Chevrolet Performance LSX and similar engine blocks in ultra high performance competition applications. It starts with our Pro-Port Raw casting and is then fully CNC machined to meet the demands of a high output race engine. The casting is made from A-356 aluminum and is Hot Isostatic Pressing processed (HIP) for superior strength, durability, dimensional stability and exceptional finish quality. It also features an exhaust port flange that has been raised 0.875" for improved air flow. It also includes deeper rocker bolt holes for improved support and stability at high rpm. Victor LS-R CNC cylinder head has fully CNC’d intake ports, combustion chambers and exhaust ports. Compatible with GM SB2 valve covers. Will require an aftermarket rocker system. Pro-Port Raw version #770469 is available for custom porting applications. INSTALLATION NOTE: Recommended spark plugs are Champion RC12YC or equivalent 14mm x 3/4" reach with flat gasket seat.