Was digging though my pile of 2.0 heads and found a pair with the valve guide bosses cut down. As I remember these had dual springs on them so it makes sense that this needed to be done to make room for the smaller inner spring. Will it be expensive to restore these back to stock. The heads are in good condition other than this.

Maybe one of the experts will have a better answer but why would you need to do anything? This is a modification but I don't see how it would prevent them from performing like stock if stock springs are used. I could be missing something?

I thought the extra material on top would help support the valve guide and keep the springs from moving around.

The single springs are retained by the outer countersink, not the inner.

That is what I remember. So unless the guides are compromised there is no reason to weld.