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.
Marvin McAfee works the details...
Marvin McAfee works the details most of us will never see. Because he doesn't trust anything right out of the box, he turned this Ford Racing Sportsman block over to his machinist who treats it like a used block...
According to Marvin, new blocks...
According to Marvin, new blocks aren't always perfect right out of the crate. All the same machining done on a used block is also performed on a new block, just to be on the safe side.
Main caps are dressed on all...
Main caps are dressed on all corners to reduce stress risers and the risk of cracking. All edges are cleaned up for a smooth fit. The result is precision fit and performance.
This forward oil-galley plug...
This forward oil-galley plug is drilled .020-inch in its center to provide additional lubrication for the timing set. Drill and clean the plug before installation.
Restrictor plugs are installed...
Restrictor plugs are installed between the main and cam bearings to keep more oil where it is needed at the main bearings.
Oil passages, like this one...
Oil passages, like this one at the oil filter, are chamfered and radiused to improve oil flow.
Marvin blueprints every oil...
Marvin blueprints every oil pump, checking all clearances and graphite coating all parts, to reduce friction on start up.
A road-race oil pan from Milodon...
A road-race oil pan from Milodon keeps oil around the pick-up in hard cornering. Marvin has blueprinted the pan and massaged the baffles and doors for smooth operation.
The lifter valley gets a lot...
The lifter valley gets a lot of special treatment including drain-back screens to keep any metal trash out of the oil pan. Drains are also chamfered for smooth drainback. "You want the oil back in the pan as quickly as possible, especially if you are racing," Marvin said. GE Glyptal 1201 from The Eastwood Company is used to coat all interior surfaces. This speeds up the drainback and keeps any stray iron particles out of the oil.