[Bruce Edwards]

The 69 has a shorter deck than the later 351's. If anything the pushrods should be a bit long. If the cam goes bad and lifters cup on the bottom the pushrods will look short and the rockers will start to go off cneter and hit the retainers. If the rocker hits the retainer hard enough it will pop the valve retainers out and drop a valve into the cylinder. Very bad things start to happen.
You really need to check into your engine more.