You can do the valves, just keep in mind they're "upside down" from a later engine. The old standby Ford tool was like a modified pry bar and can be used to pry the spring down to remove the upper retainer or pry the spring up to remove the valve keepers and lower retainer. The valve then lifts up and out of the block.

Likely you have an exhaust valve that has more carbon deposits than the remedies you've tried can handle. Clean the guide and drop a new valve in and put it back together. NAPA carries the valves here. I haven't tried, but I think you could use a modern valve removal tool. It will be tight since you are working right next to the lifter. Turn the engine over so the valve is closed to start with.

You can hand lap a new valve with one of the suction cup on a stick and a little grinding compound. If your engine is a '52 or '53 it probably doesn't have hardened seats, so if you need any machining done you have to pull the block. Since your problem is intermittent a new valve should solve things.