The IAG 1000 CNC Ported Drag Cylinder Heads are designed for drag racing and competition. These fully CNC ported heads provide a significant upgrade in long term performance over the IAG 800 heads. These heads work great for cars where getting the most power with maximum reliability is the goal. The IAG 1000 heads are the best heads available for high-horsepower drag racing. They are designed to support up to 1000 BHP with supporting mods. These heads include upgraded Ferrea +1mm Valves, GSC Viton Valve Stem Seals, Upgraded GSC Valve Guides, Ferrea Dual Valve Springs with Titanium Retainers, and OEM Keepers. FA20 Heads are configured differently from their EJ counterparts. In FA20 heads the casting is split into two parts, the "lower" and the "cam towers." As the name suggests, the "Cam Towers" hold the camshafts to the cylinder head. Kelford "B" cams are available with IAG 1000 Street Cylinder Heads. When Kelford cams are chosen we also include new OEM cam towers, rockers, pivots, and valve shim caps. Each IAG 1000 FA20 DIT Cylinder Head Set starts with new OEM castings from Subaru of America. Next, you'll select whether or not you want to include our optional Kelford camshaft package. If selected, these heads will include Kelford "B" camshafts as well as new OEM cam towers, rockers, pivots, and valve shim caps.