Oil filter threads on EBA heads??

[itsa52]

I picked up a nice set of EBA heads for my Merc, Problem is some of the threads that mount the oil filter on the left head have been drilled out. Two of the threads are actually a above the upper edge of the head and are no problem.. Question is, on the middle / lower one, does the boss inside the water jacket extend all the way through or is it ended in the water jacket? I would like to drill them out for inserts, but really don't want to go onto the water jacket.

Thanks in advance.
Ken

 

[51 MERC-CT]

The bottom hole is a blind hole that is appox. .900 deep.
If it were drilled thru it would go into the combustion chamber.

 

[JSeery]

Use a depth gauge (calipers would work for this) and measure the depth of the current hole. Then drill it out to a depth slightly short of the current depth. Depending on the size of the existing hole you could just tap them to a larger size. Options might be to epoxy in studs, heli-coils, inserts, etc.