Check out brand spanking new Trick Flow GenX 225cc cylinder heads. They are complete with 65cc combustion chambers (same compression as stock), 225cc intake runners, 80cc exhaust ports, 2.055-inch intake valves, 1.575-inch exhaust valves, and titanium retainers. At the end of the day, the most important information about a cylinder head when making power is the runner flow numbers. These are measured in cubic feet per minute (cfm) and provide the most accurate reading of how a cylinder head is going to perform. While valve sizes and cubic feet of space in the runners is good information, stick to the flow numbers as a guide.