AbraCalc

Compression Ratio for 350 Chevy Small Block

Calculate the compression ratio for a classic 350 Chevy small block with a 4.00-inch bore, 3.48-inch stroke, and 64cc combustion chamber.

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How to use this tool

  1. Enter the cylinder bore diameter and stroke length in millimeters.
  2. Enter the combustion chamber (clearance) volume in cc from the cylinder head specs.
  3. The calculator returns swept volume and compression ratio.

The 350 Chevy small block is one of the most popular engines ever built — use this calculator to find its compression ratio based on your specific bore, stroke, and head chamber volume.

Frequently asked questions

What is compression ratio?
Compression ratio is the ratio of the cylinder volume at bottom dead center to the volume at top dead center. Higher ratios increase thermal efficiency but require higher-octane fuel.
What compression ratio is best?
Most naturally aspirated gasoline engines run 9:1 to 12:1. High-performance engines reach 13:1+. Diesel engines typically use 14:1 to 25:1 for compression ignition.