Like a stereo system needs good speakers to perform, a short-block needs to be topped off with a set of killer heads. For this build we went with a set of some of the best cathedral ports on the market, Trick Flow GenX Street/Strip 235 cylinder heads. The big 235cc intake ports should feed our 454 plenty of atmosphere and they are designed for large-bore (4.125 inches and up) LS engines. The 70cc combustion chambers are CNC-profiled so that intake valves are unshrouded. This equates to more airflow and better combustion. At 0.600 of valve lift these flow 340 cfm on the intake side and 270 cfm on the exhaust side. They came assembled and ready to bolt in place with stainless 2.08-inch intake and 1.60-inch exhaust valves.