Piston Compression Ratio
Due to varying volumes between engine combustion chambers, head gasket volumes, cylinder block heights, compression heights, etc. All piston manufacturers listed / advertised compression ratios should be used as a guide only.
Actual calculated compression ratios may differ from listed / advertised compression ratios for the above reasons and variations.
To obtain an exact compression ratio, all specific measured specifications and volumes for the particular engine are required and custom pistons manufactured to suit.