SB Ford Pro-Series PRO205 205cc Aluminum Cylinder Heads. 2.08" intake, 1.60" exhaust, 58cc combustion chambers. 8mm guides, .125" raised exhaust port, 3/4" thick deck. Designed for ULTIMATE flow. Manufactured from A356-T6 aluminum. Each head comes with a detailed flow sheet. Ready for assembly and sold as pairs. Download Data here - DOWNLOAD Download Installation Tech here - DOWNLOAD NOTE: Not for use with factory pistons. Check piston to valve clearance in all applications.