Holley SysteMAX No. 300-575 aluminum heads will help take weight off the front end of the Bronco, and add tremendously to the performance compared to the wheezy iron stockers. The SysteMAX heads flow 228 cfm at 0.500-inch, which is close to the maximum lift we will see with our hydraulic roller cam. The Holley heads feature 63cc combustion chambers, and the large 2.02/1.60-inch valves are set at a 17-degree angle. The moderate 165cc intake port volume helps to preserve torque in our application. These heads come fully assembled and ready to run. Speed-O-Motive bolted them on with FelPro gaskets, using a Milodon No. 80155 head stud kit.