Head gasket thickness is the distance between the engine block and the cylinder head, when the head is properly installed and torqued.
The compressed thickness is what matters. The compressed thickness is built-in by the gasket maker. It is based on properly installing and torquing the cylinder heads.
Various thicknesses are available for many different engine models.
How is it measured?
With the heads installed, there is no good way to measure the thickness. The compressed thickness will be a listed specification for each Head Gasket.
How does it affect performance?
Head gasket thickness will impact Compression Ratio. Changing gasket thickness can be used to fine-tune compression. However, the gasket's thickness will also affect its ability to seal the combustion chamber and oil and coolant passages.
| Thinner Head Gaskets | Thicker Head Gaskets |
| Better sealing, less likely to blow | Prone to failure, because it adds space between the head and block |
| Slightly raises compression ratio | Slightly lowers compression ratio |
For most engines, we recommend the OEM gasket thickness. This will provide safe, reliable engine performance. Changing the gasket thickness should only be done when modifying an engine for high performance.