Oil Galley plugs at Camshaft

I just wanted to add to this thread with info on a threaded plug that would be the best for this issue. I needed a certain size plug for my Opel oil gallery, and the local machine shop gave me a Ford 'J' plug. It is a shallow plug with a taper on the back so that the threads have less depth. The Ford Cleveland and 429/460 blocks have the same issue: a side oil passage off of one the main galleries that is very close behind the surface.

These Ford 'J' plugs have a thread OD of about .622" halfway down the threading, and a thread pitch of 18 TPI. I am not sure what the matching tap thread is; it may be a short taper, maybe a 5/8" bottoming tap. The hole in both my 360 and 273 blocks is around .570-.575" ID, and looks like it would be right to use such a tapped hole and plug. You'd have to tap a bit at a time to make sure yo did nto tap too deep.

You can see these plugs in the pix in the 1st post of this thread:
Oil Galley Plugs