Before replacing your warped one I'd suggest you try a little home-brew machine work. Use a good flat surface, glass is good, lay down a sheet of 150 grit sandpaper and start rubbing the head on it. You'll be able to see where the high and low spots are immediately. Keep working until you have a uniform surface, concentrating on applying even pressure, then start with a finer grade of paper until you get down to about 200 to 400. You have then lapped the head and, unless the cylinder is also warped, your head gaskets should seal correctly. I'd also suggest sealing the head gasket with some brush on silver paint. The older the paint the better. There are head gasket sealers but I've never found one that worked any better than old, almost dried up, silver paint. Let us know how you make out. One more thing...if you have acorn nuts on the cylinder studs make sure thay are not bottoming out and not allowing the head to be tightened. I like to replace all acorn nuts with hex, just to be sure.
Tom