Hubert,
Sorry to be slow to answer. The hole you noticed is indeed a coolant channel. It goes vertically down to the longitudinal front to rear channel, that also ties in to the left to right channel you can see on the back of the block, with plugs on each bank. I have a display block (I presume made from a production reject) that is free of corrosion where it is clear. I will try to remember to bring my camera to the shop.
-Steve
Sorry to be slow to answer. The hole you noticed is indeed a coolant channel. It goes vertically down to the longitudinal front to rear channel, that also ties in to the left to right channel you can see on the back of the block, with plugs on each bank. I have a display block (I presume made from a production reject) that is free of corrosion where it is clear. I will try to remember to bring my camera to the shop.
-Steve