Because an engine may be borderline in regards to the compression ratio when it comes to ignition timing or fuel octane requirements, it’s important that all values used in the compression ratio calculation be as accurate as possible. This includes the head gasket volume which many times isn’t stated on the package or in any reference material. For a conventional or mainstream engine where the fire ring in the head gasket is perfectly round, the hole size in the gasket can be measured and the volume calculated appropriately. But the Ford Y-Block has an irregular shape to the fire ring seal which throws special nuances into the measuring of this volume. But there’s no need for guess work when it comes to obtaining this volume value as it can be derived by doing some simple measurements on an existing head gasket and then performing a little bit of math. Continue reading “Head Gasket Volume Calculation”