29. These are our CNC-ported Trick Flow 205cc intake port heads with a 58cc chamber and 2.00/1.575-inch valves courtesy of Summit Racing. Think these heads are great? At 0.500 lift TFS claims 299 cfm on the intake and 220 cfm on the exhaust. At 0.600-inch lift, the intake flow jumps to 316 cfm, with torque and horsepower ratings in the low to mid 400s.