Jeff Dorton of Automotive Specialists demonstrates the proper procedure for cc'ing the combustion chambers on the cylinder heads. Before beginning, any changes to the chamber should already be made, including valve seats. Using the same valves you plan to run, coat the seats with a thin layer of grease and slide the valves into place. Spin them around on the seats a time or two to make sure the grease is evenly distributed, and wipe away the excess. This will ensure a good seal. If the valves and springs are already installed, this step is not necessary.