Hello, does anyone know if it is possible to damage the valves with repeated cranking after the timing gear fails? In other words if the gear fails and the chain is jumping can the pistons hit the valves and bend them? It is a 1970 Cutlass 350 basically stock.

 

The chance of bending valves on that motor from cranking it is VERY low. If it is a factory 4bbl high compression motor AND it jumped at a high RPM then it may have bent one or more valves.

My thought...replace the chain and gears and stop, don't put the front cover and do a compression test. If the compression is bad decide what you want to do. If the compression is good, remove the oil pan and clean the oil pump pickup screen of the old gear pieces, put the front cover on and then the oil pan.

Another method would be to remove all of the rocker arms and put compressed air in the cylinders to see if it blows out either the intake and/or the exhaust.

Good luck!!!