[Tom Vaught]

Article in High Performance Pontiac (by Ray Bohacz) about a Paxton Supercharged 467 cid (4.185" bore/ 4.250" stroke) with an Butler/Eagle Forged crankshaft and a set of ported cast iron heads. The 6X heads (96cc) flowed 250/186 cfm at 28" test pressure at .600" lift.

An outfit called Gear Head Designs provided the Paxton Supercharger Kit and a machine shop/ dyno place called Racekrafters Automotive Machine, I assume, did the Machine work/ engine assembly/dyno testing.

To cut to the chase, at 7psi boost at 5200 rpm they made 647 hp and they made 680 lbs/ft of torque at 4500 rpm. (That ought to move the old Pontiac down the road in a brisk manner). They tested with a Snow Injection System, with an air/air inter-cooler, and 100 octane plus "Rocket Fuel" gasoline. Not bad numbers really for a cast iron head engine with 9 to 1 compression, GOOD GAS, and a small 224/230 Hydraulic Roller camshaft with .552"/.561" lift on a 110 C/L camshaft.

As a comparison, a couple of years ago, Luhn Performance tested a 462 engine with 2-bolt mains and a Scat Forged crankshaft, with 310 cfm (mildly ported) aluminum Edelbrock heads, a slightly lower compression ratio, and a slightly larger camshaft to match the extra cylinder head flow. The superchargers were basically rated the same HP 820 HP for the Vortech unit vs 825 HP for the Paxton unit. (Both superchargers are made by the same company that owns both Paxton and Vortech). They just look different on the outside of the case.

At the same 5300 rpm, the Luhn set-up made 863 HP and 891 lbs/ft of torque at approximately the same rpm as the testing above.

The differences as reported above were: 1/2 point lower compression ratio, 20 degrees more camshaft duration, 60 cfm more head flow, a water-to-air inter-cooler (vs the air to air unit used above) and 6 more psi of boost (13 psi).

So basically this confirms that you can easily have a mild 600 hp set-up or you can have a slightly more expensive aluminum head set-up with a different tune-up and make an easy 200+ more horsepower (by turning the boost up a few more psi) at the same rpm.

Tom Vaught