A joint venture between Mopar Performance and Chapman, the CNC ported heads are available in two versions, a standard port (PN P4876383) and another with Max Wedge-sized intake ports (PN P4876386). Advertised peak intake flow is 351 and 381 cfm, respectively. We got a hold of a set of the big port heads, ran them on the bench and found an honest 382 cfm. Exhaust flow is advertised at 252 cfm at .700-inch lift for both heads, and we came up with exactly that figure, and 260 cfm at .800-inch lift. Adding a pipe to the exhaust raised flow to a peak of 301 cfm.