If you look closely at the gasket picture and the following of the head, one can see that the oil hole that comes out of the block on the drivers side needs to feed the passage at the center of the head. As a result they gouged a groove from one side to the other.
If you look closely at the gasket it can be seen that the holes footprint on the gasket was real narrow on the ngine side. The gaskes metal plate is blown upward. It is my guess that as the gasket failed the oil from the passage got into the #1 cylinder one time so great that the hydro lock blasted the oil up through the gasket.
I presume that our second compression check that looked even with the rest was the result of filling the cylinder with oil during the checks of the other cylinders.
The reason I post is that this now is appearing to be a pattern failure. Maybe it is one that many know of. We wouldn't have been into this motor except the customer OKed an overhaul. Boy is he going to be tickled.
Bosch Master, ASE Master, L1
33 years MB technician