Chevrolet Engine Serial Number Prefixes
By John Milliman

       "Is THAT the original engine?" The question can often strike fear into your heart!

        So what you haven't gotten it off the trailer yet! No need to answer, "Heck if I know!

        Determining what engine that is under the hood of your Big Bolt can often be your first task when determining the originality of an old truck, but it's not hard. All you have to do to find out the year and displacement of that engine is scrape the crud off the pad just behind the distributor and read the the engine's serial number -- the letters and numbers in front of the actual engine serial number will tell you the year and displacement of the engine.

        Although the engine's casting number (casting numbers are available at Inliners) will give you detailed information about where and when your engine was made, the serial number prefix is pretty easy to read and will at least get you started correctly.

        The first table at right is for pre-'54 235 CID engines. These engines have babbit rod bearings and are splash oiled. They should not be confused with later, full oil pressure 235's.

The table below is for the 261's

v. Feb 05