In a perfect world, you add a few vital bolt-ons to your engine and it says “thank you” by way of producing more horsepower, more torque, and improved mileage. Welcome to the perfect world. Last month, we showed you the complete engine assembly of our GM Performance Parts LSX376 crate engine, complete with MagnaCharger TVS2300 supercharger, American Racing Headers long-tube headers, Lingenfelter heavy-duty tensioner with billet pulleys, and ATI Racing 8-rib pulley conversion. With the engine ready to rock and roll, we loaded it up and drove over to Westech Performance, in Mira Loma, California, to see just how much power our Gen IV small-block would muster.

Built with low-compression 9:1 forged-aluminum pistons, we thought the LSX376 block would easily handle 8-9 psi of boost and make upwards of 575 hp. What we didn’t know was exactly how much boost the MagnaCharger TVS2300 would make with the 8-rib, 3-inch diameter pulley that was bolted to the snout. MagnaCharger told us that we would need a 10 percent overdriven harmonic balancer/crank pulley to give the blower more boost and to help the small-block achieve 650 hp, which was our goal. With the engine bolted to Westech Performance’s Super Flow SF-902 engine dyno, the talented team of Steve Brule and Ernie Mena, got the LSX ready to make some pulls. Ernie is a tuning guru, and to help our engine make serious power, he used Holley’s new EFI Live tuning software and LS-engine wiring harness. Holley’s new EFI Live allows minute adjustments that can quickly alter the fuel injector pulse width based on lb/hr, and it also works with older GM 24x and LSx 58x reluctor wheels, and it’s 1-5 Bar MAP sensor capable. Another big perk of EFI Live is the four programmable outputs and four fully configurable inputs for multiple stages of nitrous, water/methanol control, turbocharger boost control, and the list goes on. It truly is a plug-and-play system.

Without further ado, let’s get to the good stuff and show you just how much power our LSX made.

We did it. Rated at 450 hp in naturally aspirated form, the LSX 376 and MagnaCharger combined to add 243 additional horses, an increase of 54-percent in power. This should easily provide low 11-second quarter-mile passes for our 4,300-pound Sierra. Nearly 700 hp from a 376ci small-block is no joke and we can’t wait to drop in our engine and smoke some tires. Check back next month to see us mate our Tremec T-56 Magnum and Ram clutch to this Gen IV beast.

Westech Performance
11098 Venture Drive
Unit C
Mira Loma
CA  91752
Chevrolet Performance Parts
P.O. Box 33170
MI  48232
Lingenfelter Performance Engineering
1990 Knoll Drive
CA  93003