Hans, that's not really alot of coolant lost. it could simply be a bad fit between the waterpump and the block.
Could it the hydrocarbon problem be bad rings? Are you getting even and high pressure readings from all cylinders? Just because It's burning oil, doesn't mean you'll see it. Are you having to add a quart of oil every five hundred miles or less? This is generally the first place I'd look.
If it is the head gasket, check the block and heads with a straight edge and a feeler gauge as the aluminum block and heads really like to warp. One of the reason older Harley's leak oil at the base of the jug is because the metal around the stud pulls up. The uneven surface prevents the gasket from working properly.