Well surprise surprise, I am stripping the complete engine. One of the heads is now off and stripped of valves. Turns out I seem to have a ‘big valve’ head 🙂 as the valves are larger (1.71/1.46) than the spec in my early issue WSM. I dont know if mine are stock or not (casting code is C4 so that sounds about right)?

The heads are in great shape for such an old engine. Very little guide wear in evidence. The valve seats are not pitted or sunken as I might have expected, so just need to lap the valves into the seats with grinding paste. Lots of old carbon to clean off though which should improve gas flow.

I noticed there is a small ridge at the top of the cylinders. I read that this could be cut off with a special tool. I havent pulled the pistons yet but the cylinders look good and smooth, so I hope they are OK to reuse.

I will have to decide whether to replace rings and bearings. I dont want to do a cylinder rebore as it runs well enough, and a full rebuild on a 260 will cost more then replacing engine with a 302, without the benefit of the 302 performance. as 260 pistons are pricey/rare.