Engine: freeze plug or not???

[cobraman428]

I have my 289 engine out of the car with clutch housing off and while at it, I am replacing freeze plugs. There appears to be two on the backside of the block. One seems to be a cover for the back of the camshaft which I think I will leave. The second is a smaller plug to the left in alignment with the distributor shaft. Is this just a plug or does it have coolant that runs behind it that could corrode?

[5brown1]

It is for access to a plug in the oil system - no coolant there.

[StudeRich]

You have only (6) 1 1/2 Inch Core Plugs, Flat domed Disc type on '51 to early '62 Partial Flow Oil Filter Blocks, and 1 1/2 Inch Shallow CUP Type on Late '62-'64 Full Flow Engines.