New CNC port designs now available from EMPI. These new port designs include most of what DRD Racing Heads previously offered. These heads feature beefed-up Intake & Exhaust Ports for massive porting without the need for welding. Special aluminum alloy for strength and durability...Plus they are repairable. Added material surrounding the combustion chamber for deep fly cutting. Exhaust air passages are clear for proper cooling. Comes with 12mm, 3/4" reach plug holes. These heads also feature competition dual valve springs, chromoly retainers, hardened keepers, bronze valve guides, stainless steel valves & custom fit gaskets included with each pair. Hi-Performance 3-angle valve job with stainless steel valves. Lash Caps P/N 4006 are required in all cylinder head applications that have stainless steel valves.