Engine Block Specifications. Casting Numbers: 12566910. Material: Aluminum. Displacement: 5.3L / 325 cid. Bore Dia. 3.780 in.

The LM4 was also known as the Vortec 5300. L33. The L33 was introduced in 2005 as the "High Performance" 5.3L engine. It was only available in the 1/2 ton, 4WD, extended cab Silverado …

The LM4 and L33 are as light as the LS1/LS6, but have thicker cylinder walls to handle boost and nitrous. 850 hp. can be supported with upgraded internals. Although the LM4 has an aluminum …

The LH6 replaced the LM4 in 2005. It was the first Gen. 4 LS truck engine and offered Active Fuel Management (AFM). The LH6 was available in GM mid-size SUVs until 2009. It was also …

LR4. The LR4 was introduced in 1999. Along with the LM7 and LQ4, they were the first LS truck engines.The LR4 was available in GM pickups, vans, and SUVs until 2007.

Chevrolet's 3rd and 4th generation small block engines are generally known by their RPO code. You can determine the RPO code if you have the Vehicle Identification Number (VIN) from the …

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The following specs apply to RPO codes: LS1; LS6; LM4; L33 **Click the blue links in the table for more detailed information**

LH6 The LH6 replaced the LM4 in 2005. It was the first Gen. 4 LS truck engine and offered Active Fuel Management (AFM). The LH6 was available in GM mid-size SUVs until 2009. It was also …

Application Information. VIN 8th Digit. Year. Make. Model. B. 2005-2007. Chevrolet. Silverado 1500, extended cab, 4WD. GMC. Sierra 1500, extended cab, 4WD