I ordered replacement gaskets for my engine and an aluminum head gasket was included. There was no gasket in the engine from the factory. This gasket is soft aluminum, about .012 thick. Is it used to lower compression, or to seal the head better and increase compression? I'll be running the engine on saturday with the new bearings installed, and the new head gasket. Is this gasket a stock item, or is it used only for high nitro fuels?

Thanks

The engine does have a gasket from the factory. It fits very closely in the groove that the top of the liner goes into. You need the very sharp tip of a#11 blade to work the gasket out.

If you added the gasket that came in the gasket set without removing the old one, then your engine will be undercompressed for regular fuels. You'll likely have running problems.