Hummmm.... the exposed threads do not look so bad from that angle. Those adjusters are not stock so I was probably fooled on the depth. Some variation in the exposed thread is to be expected.
Have the heads been milled on this engine? Or the block deck milled? That could explain some of the pushrod length situation.
Also, if the valves are longer than stock and/or are excessively sunk in the heads, that would push the pushrod ends of the rockers downward and put the pushrods close to the hole as shown in your pix and cause the pushrods to be shortened.
