Engine Block Specifications. Casting Numbers: 12567392, 12567393, 12551358. Material: Iron. Displacement: 5.3L / 325 cid ...

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. It was a 4.8L engine known as the Vortec 4800. LM7. The LM7 was also introduced in 1999. It was available in GM pickups, vans, and SUVs until 2007. The LM7 was a 5.3L engine known as the Vortec 5300. L59

The LR4, LM7, and L59 have very strong blocks. They can handle over 1,000 hp. using nitrous, a blower, or a turbo. However, you will need to upgrade the internals to handle that kind of power. The biggest bonus of buying a 4.8L or 5.3L engine is the low cost. They are also easier to find than the higher displacement engines.

Related Products: Camshafts & Valvetrain, Cylinder Heads, Engine Assemblies, Oiling Systems, Other Engines & Components, Pistons & Piston Rings

If you don't have the VIN, you can still identify the engine. Below you'll find pictures and descriptions to help you spot the important differences followed by an identification chart organized by displacement. Click the links in the chart for further identification and more details on that series or engine.

The information below applies to vehicles with the original engine still installed. If you have a second-hand vehicle that doesn't match the info below, the engine may have been swapped out. Follow this link for help Identifying an LS Engine by Inspection. Click on the RPO code in the table to see more details about that engine.

The LM4 was introduced in 2003 as a lightweight version of the LM7. It was available in GM SUVs until 2005. 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 and Sierra until 2007. The L33 was known as the Vortec ...

The block is secured to the engine stand. It may rotate with the added weight of the cylinder head. Installation Process. Press new Dowel Pins into the engine block. There are 2 dowels per side (in holes #7 and #8). They align the head to the block. Always replace them before installing your cylinder heads. If needed, lightly tap them in with a ...

The LY5 was introduced in 2007. It replaced the LM7 as the Vortec 5300. The LY5 was upgraded with Active Fuel Management (AFM) technology. It was available in GM pickups and SUVs until 2009. LMG. The LMG was also introduced in 2007. It replaced the L59 as the flex fuel Vortec 5300. Like the LY5, it was upgraded with AFM technology.

LM7, 5.3L, VIN code T; LQ4, 6.0L, VIN code U; How do I tell the difference? The first design (1) has a single dimple/mark on its head. The retaining sleeve is also missing from the shank. The second design (2) has two dimples/marks on its head. The retaining sleeve (3) is present on the shank. Why is it important?