LT Engines

How to Identify an LT Engine (Gen 5) by VIN

LT1 crate engine (Gen V)

(Image/LSX Magazine)

Before you begin your engine project, you need to know exactly what you have—and when it comes to General Motors’ Gen 5 LT small blocks, it’s currently a lot easier (especially with car engines) than it is to identify GM Gen 3 and Gen 4 LS small blocks.

How Do I Know Which LT Engine I Have?

There are currently just five LT engines, including the LT-based EcoTec3 truck engines: LT1, LT4, L83, L8B, and L86.

Much like with LS engines, the easiest way to be sure which LT engine you have is to check the 8th digit of the Vehicle Identification Number (VIN).

Consult these tables to identify your LT engine by VIN.

[NOTE: Take care not to confuse the letter “B” and the number “8″]


LT (Gen 5) Car Engines

8th Digit of VINRPO CodeDisplacementCommon Name
6LT46.2LLT4 (supercharged)


EcoTec3 Truck Engines

8th Digit of VINRPO CodeDisplacementCommon Name
CL835.3LEcoTec3 5.3L
RL8B5.3LEcoTec3 5.3L (with eAssist)
JL866.2LEcoTec3 6.2L
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