How to Identify a 396 Big Block

by Cassandra Tribe
Auto Engine image by Andrew Breeden from

Big-block engines came about in the mid 1950s to allow cars to hold their own on roads increasing filled with large trucks. The larger displacement designs of these engine allowed the pistons to draw more air and fuel into the engine in one cycle, increasing the car's power. Big blocks are named after the size of their displacement as measured in cubic inches (e.g., 350, 396, 440 and so on). It is easy to identify a 396 Big Block engine made by Chevy as the engine code is stamped above the timing chain cover.

Step 1

Open the hood of the engine compartment and locate the timing chain cover at the front of the engine. The timing chain cover is on the front of the engine block, above where the crank shaft connects to the drive belt pulleys, and it looks like a small dinner plate attached to the block.

Step 2

Spray the top of the timing chain cover and the area of the engine block directly above it with a spray engine degreaser. Wait a minute or two for the degreaser to begin loosening the engine grime.

Step 3

Wipe the degreaser off the engine block and timing chain cover with a clean rag.

Look for the engine identification stamp on the block, just above the timing chain cover. If the stamp is present and contains one of the following sequences of numbers, it is a 396 big-block engine: 3855061, 3855961, 3855962, 3866961, 3873858, 3902406, 3902466, 3916323, 3935440, 3955272, 3965440, 3965449, 3965540, or 3969854. If there is no stamp in this location, the engine is a different block size.


  • If the engine identification numbers read 3969854 or 3955272, the engine is considered a 396/402.


  • Never use spray degreaser on a hot engine, or there is a risk of fire. Always let the engine completely cool down before cleaning the engine block.

Items you will need

  • Spray engine degreaser
  • Clean rags

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