Please check compression numbers again wet. Do this by spraying a small quantity of oil into the cylinders so the oil settles around the piston rings. This will temporarily improve sealing and if the compression numbers rise significantly, will point you to seized or worn piston rings. If mostly unaffected, this will point to damaged valve seats or tight lash adjustment (mechanical lifters). I have seen both conditions occur as a result of overheating: Either the piston rings get seized in the pistons due to melting, or the valves recede and pound out a recess in the valve seats creating a leak. You need to do this test again wet to decide whether to do an inframe or rebuild the engine.

If it is the head your best course of action is to send the head out for rebuild. They will magnaflux for cracks, install new valves, guides and seats, and replace the valve seals. They will adjust the valve stem heights and mill the head gasket surface if required, and provide all necessary gaskets to reinstall it (if you ask nicely they may even provide torque specs) I would also send the block out for overhaul to a rebuilder because it will come back faster than you can do it at home, and best of all with a guarantee.

Consider buying a leakdown tester from the tool truck or professional tool shop. This tool when hooked up to shop air, will tell you the amount of cylinder leakage and will point you to where the leak is occurring. Compression testers are good for evaluating the overall wear on an engine, but a leakdown tester is great on its own if you have problem cylinders because it will diagnose the problem all in one step: you don't have to do a wet test to find the leak. you just listen to the carb throat, the exhaust pipe, and the open oil filler cap for a hissing sound and there's your weak spot. In the case of a blown head gasket you'll hear a hissing sound out the adjacent sparkplug hole or see bubbling through the radiator neck. Caution: be sure to bar the engine over to either TDC and lock it, or BDC so the engine doesn't kick over on you when you apply air pressure and it must be on the compression stroke, use the rotor position to guide you.