my thoughts are,why sell what u already know u have,risking something worse or a much larger headache if the newer car has issues.it sounds like ur in a pickle but what u have are easy fixes.valve cover gaskets are cake,exhaust is simple,as are the vacum lines.as long as the engine and tranny are strong a little more tlc will go along way.just my opinion.

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enjoy life,take the coal that is handed to you and turn it into diamonds. { PHILLIPIANS 4:13}