Found an L33 5.3 sitting around at the shop, going to probably pick that up…
This is what GM has to say about the L33:
One of the L33’s distinguishing features is its engine block. As with the 2004 LM4 Vortec 5300, the L33’s foundation is a cast-aluminum block with pressed-in iron cylinder liners, similar to the block used for GM Powertrain’s LS1 and LS6 car V-8s. The L33 block is exceptionally light; as a result, a fully dressed L33 is 100 pounds lighter than cast iron-block Vortec 5300s (RPOs LM7 and L59).
The L33 takes its cylinder heads from the LS6. Originally developed for the Z06 Corvette, these heads improve airflow in and out of the engine. With their pent-roof combustions chambers and new flat top pistons (the pistons in other Gen III Vortec 5300s have a slight sump in the piston deck), the L33’s compression ratio increases from 9.5:1 to 9.9:1. This increase improves the engine’s volumetric efficiency yet still allows it to achieve full power with regular grade gasoline.
Finally, the L33 is equipped with a higher-lift camshaft. Maximum valve lift increases from 11.6 mm on the LM7 and L59 to 12.5 mm. The new cam and compression ratio are the primary sources of the L33’s increased horsepower.
LS6 Intake
LS6 Fuel Rail
LS6 Injectors
LS1 Throttle Body
Vorshlag 1 7/8″ Primary Headers
Cam swap after the swap is completed and tested.
So basically a 5.3L LS6 with a cam.
