Cylinder head prices range from $125-$185 depending on where you get it and which cylinder it is. Those are aftermarket prices, don't know dealer prices, probably a little higher. Two hours labor sounds inline, maybe a little low if they have to fully remove hoods, exhaust and intake manifolds, etc. With new gaskets, head, valve work, and carb work, I would have quoted it between $350-$450, but remember I have not seen it. After I torn it down I would have at least reconditioned the valves, if not replaced them. This could push the price up to $500. My labor rate is $70/hr. for Kaws. Just my opinion, which according to some on this forum is not worth much, because he is a professional and I'm not.