This month, we bring our GM Performance Parts ZZ502 crate motor buildup to a close, with one last, final run at the dyno that ends with blistering performance, jaw-dropping dyno numbers, and a high-five to engine-builder Steve Brul. The first two installments of this series shed light on the easy-to-install bolt-on parts, which took us from a mild-mannered but healthy 530hp engine to a king-for-a-day-status 740hp brute. These numbers are nothing to sneeze at, and for a motor that can be built in a weekend for less than $12,000 and still run on 91-octane fuel, we feel that this combo was worth every penny. But we're horsepower junkies, and you know what that means: We can't leave well enough alone when we know that there is more power to be made, more bling-bling to be applied, and more fun to be had. With this "more power equals more fun" mantra ringing in our ears, we tore apart our perfectly good motor in preparation for its rebirth.

After the beast was in pieces, we ventured just a few miles south of Westech Performance Group's facility to see Ray Field, owner of Dougan's Racing Engines. Dougan's is a well-known and respected machine shop and engine-building facility that has performed surgery on a plethora of Gen. VI GM engines, so we felt confident it could help us out in short order.

The crew at Dougan's machined our engine block, opening up the bore size from 4.47 inches to 4.50 inches in preparation for a new set of JE blower pistons. We reused the 4-inch-stroke forged GMPP crankshaft after it received a complete balance and micropolish. We also reused the forged GMPP connecting rods after they were resized and fitted with 7/16-inch ARP bolts. The entire rotating assembly was also balanced and blueprinted.

The long-block was once again made complete with our Air Flow Research 315 CNC'd cylinder heads and a blower-specific grind camshaft from Comp Cams. To feed the hungry machine, we picked out a set of 950-cfm Holley HP-series carburetors, which were promptly bolted onto an 8-71 Weiand street supercharger.

Steve Brul, resident dyno king at Westech Performance Group, cleaned, measured, and assembled our new parts. He also lent his expert hand at tuning the engine once it was strapped onto the Superflow dyno so that we could squeeze every last ounce of power out of the engine on 91-octane fuel.

For more information on any of the parts used in this article, please contact the companies listed in the source box.