Any machine shop could check your head. You yourself could actually check the valves. Dump gas in all the ports, exhaust and intake, Hold or set the head down where the combustion chambers are down, and check the valves to make sure no liquids are coming out. Obviously your going to have to pull the cams so all the valves are closed.

If it sits for a while, and you don't see any seapage around any valves, they're good, and all you have to do is have it check to see if its flat or not.