I'd make sure I found out why the cylinder has absolutely no compression before I jumped in and spent a bunch of money on a cylinder head. You said that the head was off, start by turning the head upside down, make sure the spark plug is in and then fill the combustion chamber with solvent to see if the valves are leaking. I'd put the #6 piston at top dead center and make sure the edge of the piston isn't missing down to the ring land. Also check the pushrods to make sure that they are straight. Also maybe see if the cam lobes aren't rounded off causing the valves to not open. I've seen in the past that you can make the rest of the engine really worse off by over-doing the cylinder head
Don
