496 Chevy Big Block Build - Pump Gas Stump Puller

Behold the fruits of our labor; 496 cubic-inches of Chevy big-block goodness. Finishing off the build is a Weiand aluminum water pump (PN 9242, $99.95) and a set of very sweet Doug's headers (PN D320). Doug's has been doing headers since 1958 and these hand-built, mandrel-bent tubes are a work of art. Featuring two-inch primaries and 3.5-inch collectors, they are tuned with the proper size and length to efficiently remove all the spent gases from each cylinder. This reduces pumping loss and the result is more power and torque. The ceramic coating is for more than just looks. It can drastically lower engine bay temps and that equates to more power. Since this engine is externally balanced, Eagle supplied the balancer along with a properly worked-over flexplate. Keeping the valvetrain covered up, and looking great, is a set of fabricated valve covers from Spectre Performance (PN 5041, $136.99) and a set of Fel-Pro molded silicone and steel core gaskets (PN 1635, 42.95) inhibits leaks.

We loaded up the engine and took it over to Westech for a little time on its Superflow 901 dyno. After installing a K&N oil filter and dropping in seven quarts of Lucas oil, Westech dyno guru, Steve Brule, fired up the big-block and started making pulls and adjusting timing and fuel. After a few tries we nailed down a best pull of 593 hp at 5,900 rpm and 595 lb-ft of torque at 4,500 rpm. This was at 38 degrees of timing and 71/83 jets (8.5 power valve). Try as we might, we just couldn't sneak over the 600 mark. Out of curiosity we bolted on a one-inch open spacer and the numbers squeaked up to 596 hp at 5,900 and 598 pounds of twist at 4,500. Even though the peak was up just a touch the lower end of the pull saw a more significant gain.

If we wanted to jump over the magic 600 mark we decided we would need stiffer valve springs, 1.8 rockers, and possibly a single plane intake. Of course we could always go with a more aggressive cam, but that would veer away from our goal of building an easy to live with street engine. Besides, we're going to have a hard enough time hooking up this much power once we find a car to stuff it into.