I have seen a number of these do this. I have done the Valve Job for about $3,000 including the new valves and new hoses and injection nozzles. All have gone great with no comebacks and no burning oil. Take off the oil cap and look in, if you see clean metal and no black death (burned on oil) go for the valve job and new timing chain, sprockets and bow rail and other rails. Good luck.
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