cad58y, no doubt you realize the engine should never be turned in the CCW direction. Difficult to determine what problems that may have caused. Using a bore scope you should be able to see if any valves are stuck open, causing a mechanical interference. It's possible there is a problem with the timing chain tensioner that is causing a mechanical binding. If there are no valves contacting a piston, you may want to remove the timing chain tensioner and verify the spring has not broken. The tensioner spring keeps the timing chain tight when the engine is not running. Once the engine starts oil pressure maintains tension on the timing chain.

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Fred Hoelzle