mechanic

Clean the heads surface area with a flat piece of steel. Only resurface if they are warped. Over heating an engine can cause warping but simply resurfacing them makes them usable. If they take so much off the compression is changed then they don't know what they are doing. Any real machine shop will check the surface and resurface if needed. It is checking for cracks that can't be seen that is really important because they can detect stuff you can't. I can get some angle iron, vice grips, and some cleaner then they will look brand new. But they could be cracked. I bet you can a youtube showing you how to clean the surface of a head like I was shown. I did not come up with it that is the way shops do it. Make sure the angle iron is longer than the head is wide. As you clean the gasket material off you will see any warping. Or just take it to a shop and they can do it.

I always get parts from the junkyard. Just get what looks the best. Sometimes you can take it back and exchange it if it is bad even at a junkyard. Check return policies posted at the junkyard. As long as you aren't trying to cheat them they are cool. But remeber they deal with crooks everyday so they try to be careful.