I don't see how you can hurt a valve or piston by slowly turning over an engine by hand. Well unless you really lean on the breaker bar or 1/2 drive that you are using to turn it over with.

I am not familer with the 616 but it probably isn't all that much different then the 603 in this respect. After you free it up as was said above, then you need to time the crank to the camshaft. The FSM should provide the procedure to do this. Once that is set and the new chain is in place then worry about the IP.

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200