What’s up with this engine block plug

ArnoldRC said:

5/16"

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sooboy said:

What can I use to get it out?A piece of 5/16” square key stock?

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sooboy said:

I’m preparing my block for assembly and removing all of the plugs...there is a plug below and to the right of the cam bore .It has a square hole that is bigger than a 1/4” Drive extension end and smaller than a 3/8” drive extension.What the heck fits it?

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Paul Kane said:

It's a 3/8-NPT pipe plug. Go get yourself a pipe plug socket.

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