It can be done. Some of the foreign restorers use the method to restore heads that are no longer available. It is a long and expensive process. A lot of manhours to build it up and then it is just milled to the original specs. The cometic gaskets will save you alot of money and will have the same performance. I have used cometic gaskets and they were recommended by an experienced builder that builds alot on nitrous engines. The main thing with them is that the head and block must be milled flat for best results. You can try this site:
http://www.aluminumheads.com/