There are many other ways to "Repair" a set of cylinder heads. The Guides wear. That is jus the way it is. You can fix them if they are not to far gone by Knurling the Guides. This is my preferred method if the Guide is not beyond tolerance. Many people will state that the Knurling of the Guides just creates a worn out guide. Since you have additional metal to remove they think it will wear out sooner.
