LS3 Power Upgrades - The Power Of 3

We replaced the stock drive-by-wire throttle body with this manual version from FAST.

All testing was performed using a set of 1 3/4-inch, long-tube headers feeding 18-inch collector extensions.

The stock water pump was ditched in favor of a Meziere electric pump.

The LS3 was run with a FAST XFI management system controlling the factory injectors.

Run on the engine dyno with headers, no accessories, and tuned with the FAST XFI, the LS3 produced 485 hp at 5,900 rpm and 476 lb-ft of torque at 4,600 rpm

After running the LS3 in stock trim, we removed the coil packs and valve covers to reveal the stock rockers and valvesprings. Note the offset rockers on the intake valves.

Off came the stock LS3 heads to make room for the CNC-ported L92 heads from Total Engine Airflow (TEA).

Texas Speed supplied a custom hydraulic flat-tappet cam. Note the difference in the retaining-bolt pattern between the cam supplied by Texas Speed (left) and the factory LS3 cam. The three-bolt cam required a new timing gear from GM.

The LS3 comes with flat-top pistons without valve reliefs. Care must be taken when selecting a cam, as our Texas Speed cam was about as large as you can go while maintaining sufficient piston-to-valve clearance.

TEA supplied a set of ported L92 heads for testing. Impressive in stock form, they can support more than 700 hp. They feature 70cc combustion chambers but can easily be milled to the stock 68cc size.

The intake flow offered by the TEA L92 heads was certainly impressive. How does 370 cfm at 0.700 lift sound? That's big-block Chevy flow, from a motor that displaces just 6.2 liters.

The ported heads from TEA featured titanium retainers and a Platinum dual spring package that allowed us to run safely to 7,000 rpm without fear of valve float.