If you don't have access to the VIN — or the engine may have been swapped — you can identify your LS engine visually using casting numbers and physical characteristics.
STEP 1 — FIND THE BLOCK CASTING NUMBER: The block casting number is located on the front of the engine, typically on the passenger side of the block near the front face. It is stamped or cast into the block. Clean the area with a rag if it's oily or dirty.
COMMON LS BLOCK CASTING NUMBERS: 12564243 = LS1 or LS6 (5.7L) 12568952 = LS2 or L76 (6.0L)
Note: The same casting number can be used across multiple variants. The casting number narrows it down, but additional details (heads, intake, displacement) confirm the exact engine.
STEP 2 — VISUAL IDENTIFICATION TIPS: • LS1 and LS6: Aluminum block, aluminum heads. The LS6 is externally very similar to the LS1. The LS6 has a revised intake manifold with a more aggressive port design. • LS2: Uses a different (taller) intake manifold than the LS1/LS6, and the block casting number will differ. • Valley cover shape: The valley cover (the plate that sits between the cylinder heads over the lifter valley) changed shape between LS generations. First-gen LS engines (LS1, LS6) have a distinctive valley cover shape compared to later Gen IV engines (LS2, LS3, L92, etc.). • All LS engines are aluminum block with aluminum heads — if the block is iron, you likely have a truck-based variant (LQ4, LQ9, LM7, etc.).
STEP 3 — CONFIRM WITH US: If you're still unsure, contact us at 1-844-XPARTS-1 or support@expediaparts.com. Provide the casting number and any other details you can find, and we'll help you confirm the engine before you order.
