Am there, Doing that.

First, make sure you have a vanagon head, not a bus head. The engines are very
close and the bus heads have different (smaller) valve sizes then the vangon.

You should remove the valve springs and check the valve "rock" to see if the
guides are worn. I know this is a pain but it cost nothing to do.

Make sure you do the same work to both sides. Best to pull the other side head
too so you know its OK to.

Consider getting the heads rebuilt. for about 350 you can have Mark Stephens
rebuild them and get a 100,000 mile warrenty. He has special exhaust seats that
are tappered and then shrunk in. Never come out.