For the next test, Martin swapped the stock cylinder heads for Ford Racing's Stage 1 CNC-ported heads. These heads offer a 20-percent increase of intake flow and a 30-percent increase of exhaust flow over the stock heads. The Ford Racing intake manifold was bolted back on, but the stock camshafts will handle the valve actuation for this test. Once the engine was bolted back together, the new combination pumped out 391.2 hp and 359.5 lb-ft of torque. Next, Martin swapped the Hot Rod cams back in and reinstalled the stock intake. This resulted in 390.9 hp and 364.8 lb-ft of torque.