21HP Intek Valve Guides

Does anyone know what the specs are for the valve guide clearance on the 21 HP Intek (331877 0939 B1)? It is from a Craftsman Rider about 6-7 years old. I have not put a dial indicator on them yet but they are pretty loose!! I was burning oil BAD before I decided to rebuild. I believe the head gasket was blown between the piston and pushrod chamber so this may be where the majority of the oil was getting into the combustion chamber. Do people knurl the guides to tighten them up? I know that is what we did 30 years ago in high school when rebuilding an engine.



Thanks!



Jeff