Chiphead, I noticed you said the shop lapped the valves. With them leaving lapping compound on the valves, you know what kind of job that amounted to. Did they grind the valves and seats, or just lap them? If they weren't ground with a stone, don't waste your time using the head as is. Take it to a real machine shop and have the valves and seats ground. Then they will lap them, to make sure the seats are the right width and location, and will definitely wipe the lapping compound off.
