340 oil Galley plug help?

Is that n Offy tunnel ram?? I don’t have a good diagram, but someone will come along and post one. The plug under the main cap can be checked with a long rod. Just slide it in the hole under the main cap and it should only go down...I forgot the measurement and I don’t want tell you wrong. You should also be able to see it down in the hole.

Don’t forget the pipe plug in the back of the drivers side lifter gallery. There are two on that side. The external one you get to from the bellhousing side and it’s through that hole that you install the inner plug.