With the intake off (heads on), at the back where the intake seals up to the block there is a round spot cast into the block, with a hole going straing down. This is slightly left (towards passenger side) of center. It has a press in plug. I would guess the hole is 5/8" give or take an 1/8. I assume it is an opening to an
oil gallery. I checked a couple manuals I have. I can see this in several pictures, but there is no mention of what it is.
So is this an
oil gallery plug?
When I pulled the intake this plug was covered with a thick layer of what looks like a clear RTV sealant that was also used to seal the intake to the block. The intake does not appear to have a flat spot over this area to make a seal, so I must assume this sealant was just glued to it. It was stuck fairly tight, but came out while cleaning the block with a razor blade type scraper.
Should this be there?