LT Engines

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

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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  1. Jacob c LaPoint says:

    How do you verify visually that someone didn’t put a 5.3 in a truck that is supposed to have a l86? I bought a 2015 sierra denali which says it has a 6.2 but I know the engine was warranty replaced at some point and I want to make sure it has the correct engine. It doesn’t have the power I believe it should.

    • Anybody know about it? Does it has differneces in visual ?

      • Adrian Mejia says:

        Check the casting number of the cylinder head which is located just between the valve cover and the exhaust manifold on the passenger side on the side of the cylinder head. Should read 12685669.

  2. Asa campbell says:

    I have a 2019 AT4 GMC Sierra. My 8th digit is L. What the heck???

  3. Ralph Flores says:

    where can i find the nerf bars/side steps for my 2000 Chevy silverado 2500HD crew cab pickup? i have looked everywhere. the center to center body mount bolts front to rear span is 85 inches with one in the middle. everything that has been sent to me is C to C is 75 inches.VIN 1GCGC23R7YF404896. IS IT A CREW CAB OR EXTENDED CAB? 4 full size doors. no dealer can helpme nor any online companies.i just can’t find the right size HELP!

    • Paul Sakalas says:

      Hey Ralph, it looks like you may have some options. Go Rhino offers a set for the 2000 C2500 crew cab, according to their website. N-Fab and Westin do as well, again, according to their respective websites.
      But to make sure, you may want to talk to those folks directly, as there are different bed and cab configurations to consider. Thanks for reading, and good luck with your search!

  4. The number on the back of my engine block on the driver rear side is 1P*6FR150697 what year is my engine. Was told it was a 2016.

  5. Marty Zachry says:

    On my Chevy Silverado the 8th digit is a G , what does this mean thanks

  6. ok so what is a LT2 then

  7. John Bradley says:

    i see that Vortec= LS and Echo = LT; well the 8th letter in my vin is a C which means its a LT but the moter is a Vortec meaning LS so which one is it

    • If your vehicle is a Gen 5, and your 8th digit is a C, you have an L83. Naming convention between LS/LT/Vortec does not matter once you have the RPO.

  8. Brian Higgins says:

    My 2001 Chevy Silverado 1500 crew cab, 8th digit of VIN # is a “T”. I don’t see that having an explanation? Can someone please help me? I just want to know what model I have so I can get a part and order it. Thank you


  10. Billy N Cole says:


    Base – LS – LT ?

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