I don't know the VIN. Which LS engine do I have?

Before you begin any project, you need to know the starting point. When it comes to Chevrolet's 3rd and 4th generation small blocks, there can be a lot of confusion.

There are more than 40 variations of these engines. The similarities between them make a lot of parts interchangeable. However, there are differences between them too. To get the right parts, you need to know which version of the LS you are starting with.

The easiest way to tell the difference is to check the 8th digit of the VIN code on the original vehicle.

• Follow this link to Identify an LS Engine by VIN.

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.

**Please note that this guide is intended for stock engines. If the engine you are looking at has been modified, the guide may not give you the right answer.**

Displacement  Markings and Block Material

The displacement will be cast into the metal at the front (or rear) of the block, just below the cylinder head. While you're there, check to see if the block is aluminum or cast iron. If you're not sure, check it with a magnet. Cast iron is magnetic while aluminum is not.

Timing Cover

The timing cover will tell you whether you have a Gen. 3 or Gen. 4. If there are sensors in your timing cover, you have a Gen. 4.

Intake Manifold

The intake manifold will tell you whether the engine came from a truck or a car.

• The car manifold has a rounded top and you can see the contour of the intake runners.
• The truck manifold is about 3 in. taller and has more of a box shape.
• If you see a supercharger you can skip the chart. You have either an LSA or LS9

Identification Chart