Hot Rods 1940 Ford Master Cylinder Cap

Anyone know of a source or a part number for 1940 Master Cylinder Cap? The fluid in my coupe was all nasty and black so I finally got up the motivation today to flush it out...got it all squared away and tightened up the last bleeder valve and the damn cap won't go back on...it seems to be aluminum and is stripped.
I would THINK some parts store would sell one- even the plastic ones but nothing is showing up online. Anyone know of a local (Napa, O'Reilly's, Advance, Etc.) source or part number?

Thanks in advance.

 

Same cap from 1939-48, and 48-56 pickups, if you know anyone with some spare parts.

 

Seems like a pipe plug of a specific size should work- that’s probably too easy and cheap though.

 

I have sent you a PM.

 

The threads are not pipe, they are straight and use a flat gasket to seal at the top.

 

Plus it is vented!

 

AVater- I Thought I responded but the iPhone screwed me! I just sent a PM.

Ahhh. Vented. I guess that's what those tiny little holes are for. Is that because it's the low point of the system? I don't recall any of my firewall mounted masters having vents but maybe I just don't know any better.

 

anybody know the thread?i would like to make a bleeding adapter to pressurize

 

The Part # for a 1939 thru 41 master cylinder cap is 91A-2162-A.
It looks like the cap shown in my HAMB add. I drilled a hole in the top of the cap
for the bolt you see so I could pressurize the system. 1940 Ford Master Cylinder with Bracket | The H.A.M.B. (jalopyjournal.com)
PS: I believe 1939-48 Ford car master cylinder caps are all the same.