Here is a tool to use with a standard air hammer to remove insert type automotive valve guides.  This tool pilot is .305" diameter and designed for removing and installing .312" AND  8 MM valve guides.  This really speeds up the task of removing and installing valve guides during a cylinder head reconditioning job. We recommend you use a fairly powerful air hammer to drive this tool, some of the cheaper or lighter weight air hammers have problem with stuck guides.  Please check our other listing for similar tools for larger and smaller valve guide remover and installer tools.