Stock Sux Part 1:
How to get un-sucked. Case in point: ’03 Silverado

Text and Photos by Ro McGonegal
VOLUME 1, ISSUE 2

This is about function and practicality on top of a big lump of grunt, and has little to do with outward appearance. It’s about how far you can go with the drivetrain and still maintain a civil, powerful, fun-to-drive mode of transportation that relinquishes none of its inherent qualities. Sluggo (you can call it whatever you want) plays to my middle-age sensibilities. It can carry a bulky, heavy load, it’s roomy, seats four comfortably, and offers a big margin of safety in its heft. Beside, I like driving the damn thing.
The premise for the Silverado embraced the ethic I’ve had ever since cars became my obsession. Call it a regional anomaly. I grew up in the northeast, in a doorslammer nation where race cars still looked a lot like the street cars they sprang from. A factory-built car with a roof and doors became my fetish, not the spindly rails of a dragster that looked like nothing that ever came off a Detroit assembly line.
The strategy throughout was to encourage low-end torque, up horsepower, and maintain a semblance of fuel mileage from the most common LS-series engine, the LM7 5.3L V8). In stock form, this 325ci aluminum head/iron block engine produces 285hp at 5,300 rpm and 325 lb-ft at 4,000 rpm. With a flat-top piston, the 61.5cc combustion chambers yield a static compression ratio of 9.5:1. Intake- and exhaust-port volume is 210 and 75cc, respectively, and the valves are 1.89 and 1.55 inches.
When the rest of the world finally shucks the venerable small-block, it will find an amazingly simple though highly-engineered work of art ready to thump in stock form. From the bottom end up, you’d swear you were looking at a sophisticated import V8, more recently of the Japanese or German variety. We know unequivocally that in completely stock form even the cast-part lower echelon LS engine will absorb tremendous abuse (skillions of 700hp pulls on nitrous oxide) without failure. If it can withstand heinous, heaped-on terror as a dynamometer mutt, it’s quite likely to live the life of Methuselah on the open road.
Armed with this knowledge, I worked with Vinci Hi-Performance (VHP) in Maitland, FL, to encompass the usual bolt-on suspects and then advance to more involved systems, but without opening up the short-block assembly. In effect, it’s all bolt-on, but it doesn’t necessarily bolt right on. All the brands we used were favorites of VHP’s, stuff they recommend or incorporate on a regular basis. To support a 100 percent increase in wheel horsepower, I also put the upgrade whammy on the brakes, suspension, transmission, rims, and tires (more about that next month).