The Brodix Dragon Slayer series small block Chevy aluminum cylinder heads are the definition of economical Out-of-the-Box horsepower the 23 degree Dragon Slayer DS 225 series cylinder head comes standard with CNC ported combustion chambers allowing this port to flow over 300 CFM at .600'' cam lift. Every casting is poured from a-356 virgin aluminum and tested before Brodix utilizes their in-house processes such as finish machining and heat treating to assure that you receive the best products for your hard-earned money. Solid, phosphorous bronze guides are used to reduce valve leakage and oil consumption. The ductile Iron valve seats are installed for use with unleaded fuel. This head is also milled and drilled on the ends for accessory mounts and uses the traditional perimeter-style 4-bolt pattern valve cover and only offered with the straight spark plug angle configuration. The best thing about this Big flowing head is that All standard components such as rockers, lifters and intake manifold may be used sold in pairs.