The EMPI GTV-2 Cylinder head casting out-classes all the competition! Beefed up Intake & Exhaust Ports allow massive porting without the need for welding. Special Aluminum Alloy for Strength and Durability and is repairable. Intake & Exhaust ports are 20% larger than stock. Has added material surrounding the Combustion Chamber for deep fly cutting. Thick interior walls for porting. Exhaust Air Passages are clear for excellent cooling. Machined for 12mm 3/4" Reach Plug. The GTV-2 Casting allows you to run as-is - an exceptional Performance Head, or have any Hand or CNC Port configuration from Mild to Wild! All EMPI Complete Heads are supplied with Stainless Steel Valves. Lash Caps P/N 4006 are required in all cylinder head applications that have Stainless Steel Valves. Bare Head comes with 40 x 35.5mm Valve Seats and Bronze Valve Guides installed. Rocker, Exhaust and Intake Studs are included. Standard 85.5mm Bore and 58cc Chamber.