I was looking at my set of heads and thought it would be a good idea to start off by blocking off the EGR passage before I start porting.
Trying to weld a little peace of steel over it could be realy hard to do plus it would be bad if I arced the valve hole lip or a bit metal spatter stuck to it or the valve guide hole.
I can't use any thing that might chip off, because the only reason I have these heads is to prep a turbo set up over the next 3 years to take back with me.
I can't have bits of hard materal getting blown through the spining turbine.
Any one know of any thing that would cover that passage up and stay in one place?

 

Put a freeze plug in the hole.

 

I should have described it more.
The passage is a smaller square passage in side the head heading tord the intake side.