If you think you have a bent pushrod the best way to determine if this is indeed the issue is to remove rocker cover. When you pull off the rocker cover you will be able to see the valve train. If you don’t see any damage you will need to slowly turn over the engine to check if the valves operating properly as the engine rotates. It may be necessary to check the clearance of each valve individually. When you notice a rocker or valve not operating like the rest, you found the bad pushrod.