The Chevrolet Vortec 5300 L33 engine is an aluminum block 5.3L LS-series engine used in trucks like the Chevy Silverado and GMC Sierra. Quoting the Wikipedia article section on the engine’s specifics:
The Vortec 5300 L33 (VIN code “B”) is an aluminum block version of the LM7, and was referred to as the Vortec 5300 HO in marketing materials. How ever it should be noted that the L33 uses a flat top piston from the 4.8L instead of the standard dish piston found in the LM7. It also uses 799 cylinder heads, which are identical to the 243 casting found on the LS6 and LS2 with the exception to the Corvette spec valve springs, and hollow stem exhaust valves on the 2002-2004 LS6. This combination increased the compression from 9.5:1 to 10.0:1. Also the L33 had a specific camshaft not shared with any other engine, with lobe lift of 7.2 mm, 193 degrees of intake and exhaust duration, and a 116 degree lobe separation angle. As a result power increased by 15 hp (11 kW), to 310 hp (230 kW) and 335 lb·ft (441 N·m). It was only available on extended cab 4WD pickup trucks. Only 25% of trucks made in 2005 had the L33 engine.
Specifically, the engine is found in 2005-2007 Silverado 1500 4WD and GMC Sierra 1500 4WD trucks.
To put a set of Jenvey Dynamics individual throttle bodies onto this engine, you will need the following parts built around the LS1/2/6 kit: