Manufactured from genuine Ford/Cosworth castings, we are now able to supply brand new BDR cylinder heads with 4 stud exhaust pattern. All castings are supplied fully machined with hardened valve seats and bronze guides fitted. The standard seats can take inlet valves up to 1.275" and exhaust valves up to 1.070" diameters. Heads can be prepared to take alternative valve sizes. The ports are not machined and therefore can be ported to customer’s own specification. Combustion chamber volume is 31cc. Spark plug thread 10mm. Please call for BDG spec heads.