Blanking plug for breather union (early engines)

Hi guys,

I am looking for a a blanking plug (grub screw style) to replace the elbow breather union fitted to 750 engines up to 1971. I've seen them on several engines depicted here.
Thread should be 1/2"-20 BSC. Who sells them?

Rgds. Knut

Although theirs is UNF.

At one time I had a small block chevy drain plug in the location, so it does not have to be BSC to seal.

Try a search on 1/2-20 x 1/2 socket set screws. Finding them in stainless is the only hurdle I experienced.

That said a socket button head with a copper gasket would be better.