Ford Racing sent us its Stage 3 CNC-ported cylinder heads, which we also tested. These heads feature larger valves (35mm intake/38.5mm exhaust) for an increase in flow over the Stage 1 CNC-ported heads that we previously tested. The Stage 3 heads flow 291 cfm at 0.600-inch lift on the intake side and 191 cfm at 0.600-inch life on the exhaust side. Stock heads come with 34mm intake valves and 37.5mm exhaust valves, and flow 223 cfm at 0.600-inch lift on the intake side and 153 cfm at 0.600-inch lift through the exhaust valves. With the Hot Rod cams and the Stage 3 heads installed, Martin bolted the stock intake manifold on for our first test with the larger cylinder heads. When the pull was over, we were very happy to see 404.2 hp and 362.4 lb-ft of torque.