Big boost power is the name of the game, and this month we're bringing the high-performance Chevy crowd a quadruple-digit power play. The test subject is a 496ci Rat witha Comp valvetrain, Dart induction, a Carb Shop carburetor, and an F2 Procharger capable of moving enough air to make a category five hurricane jealous. We wanted to see what a concoction of such magnitude could potentially deliver on an engine dyno, so we commissioned the Westech dyno facility to give our boosted beast a run across its Superflow polygraph.
After many months of preparation, the engine finally made its way onto a dyno cart, only to reveal a number of hurdles yet to overcome. The first was interference between the F2 blower case and the driver-side valve cover. Our immediate reaction was to warm up the TIG welder and clearance the valve covers, but thanks to the quick thinking of one of the guys in the shop, we tried a pair of aluminum Moroso pieces. Sure enough, they fit perfectly and we were ready for the next challenge.
Next we learned that ProCharger's 8mm cog belt wouldn't allow us to fit an electric water pump overthe Comp Cam beltdrive system. So the guys at Westech temporarily rigged up a boat-style setup that carried water directly from the dyno water tank to the engine. If you run into a similar situation for the street, you could use a block-off plate with AN fittings, allowing you to place a remote water pump anywhere you'd like. Matter of fact, most if not all are required to do this, unless you're utilizing a factory timing cover. In our case, we opted for Comp's beltdrive, since it would allow us to advance or retard the timing in a matter of minutes and make for easy cam swaps.
Last but not least, we had to fabricate a 311/42-inch aluminum pipe from the F2 head unit to the 4150-style Holley HP carburetor. We contemplated incorporating an air-to-air intercooler but found it too time-consuming for this month's editorial deadline. Instead, we funneled the air directly from the blower to the carb with a bypass valve (surge valve) in between. After measuring the proper length and cutting it, we bead-rolled the outer lips of the aluminum tubing and covered them with high-pressure hoses. We used a 77-tooth cog pulley at the crank and a 48-tooth cog pulley up top at the blower.
Induction consisted of a Dart...
Induction consisted of a Dart single-plane manifold and a killer set of Dart/HVH Pro 1 CNC-ported 335s. We should note that these heads were available complete, but because of our combination we ordered the bare/CNC heads from HVH and outfitted them with a complete Comp valvetrain. Expect to pay $3,450 for the trick castings.
We used a remote-style water...
We used a remote-style water system from a boat to keep the engine cool; however, for street-driven rats, contact any reputable water pump manufacturer for a specific application.