Jim Smart
August 9, 2007

Iron Heads And A Hot Roller Cam
You might be lulled into believing aftermarket aluminum heads are necessary to achieve 400/400, but Marvin proves otherwise. Make 400 honest horsepower and 400 lbs-ft of torque with ported Ford 289/302 cylinder-head iron castings. PowerHeads performs a CNC-port job, along with a five-angle valve job that includes hardened exhaust valve seats, new guides, and new stainless steel 1.94/1.60-inch valves. Comp Cams has provided Marvin with 100 percent of the valvetrain system, which includes dual springs with dampers, steel retainers and keepers, and a hydraulic roller camshaft long on torque. Marvin chose a Milodon dual-roller timing set. Comp Cams 1.7:1-ratio roller rockers were also inspected and blueprinted by Marvin. ARP screw-in rocker-arm studs with guide plates get everything square on top.

Marvin has opted for an aggressive hydraulic roller camshaft that gives him a lot of lift (.544) and enough duration (212 intake, 218 exhaust at .050 lift), with a lobe separation of 112 degrees that provides ample low-speed vacuum for power brakes, and other accessories we need on the street.