State of the art foundry allows for the most precise out-of-the-box cylinder castings available. The 18SPX flows over 325 cfm with only the bowls blended, ports matched to the gasket and a three angle valve job. Standard combustion chambers are approx. 68cc and can be milled to the mid 50cc. Complete heads feature spread port exhaust, 2.14 intake with 1.60 exhaust, roller springs (up to 700 lift), titanium retainers and 10deg. machined locks. Prices per pair.