Sounds like you need to adjust the valves. if the rings were bad it would be leaking into the crankcase the overheating needs to be addressed too. could be low on coolant, bad radiator, or bad thermostat or bad water pump. it seems premature to pull the head. pulling the head a a boat load of work.. you don't want to do that unless you are sure it is necessary.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.