1966 1967 9 inch fill plug

[anghelrestorations]

Looking for a fill plug for a factory 9 inch rear end for a 1967....but should be the same for a 1966 as well.  Im not aware anyone makes a reproduction of this?
The fill plug I have doesnt seem right with the beveled edges so dont think this will seal correctly.  If anyone has an extra let me know.

Ford part number - Axle Filler Plug 379166-S

Marcus
602 628 2522
marcus@anghelrestorations.com



20251111_162058 by Marcus Anghel, on Flickr


20251111_162107 by Marcus Anghel, on Flickr

[Royce Peterson]

The one in your pictures looks correct - it needs a copper washer to seal.

[anghelrestorations]

Royce, Actually I dont think what I am showing there is correct.  If you look closely there is no way to seal it with a gasket or washer.  That beveled edge would not allow that. 

Here is what I would consider correct and I think you are referring to:

20251117_132432 by Marcus Anghel, on Flickr

[pbf777]

    The threads in the back cover-plate are somewhat recessed as the hole is punched and the threads utilize the rolled material provided in the circumference bellow the 90 degree turn ; and therefore the beveled edge provides the service of aligning the greater diameter gasket needed in order to move the sealing surface out onto the flatter surface of the cover away from that radius. But the gasket thickness may be a concern so as that the bevel on the nut doesn't stop against the radius before compressing the gasket; where in the latter example such wouldn't be the case.   

    And although I do understand the possible intended purpose in the bevel as presented on the first as inquired of plug, that doesn't mean I'm attempting to state that it is "correct"; but somehow, as unique is that plug is, and that it does seem interesting "close", I'm thinking chances are that it 'is' a "rear differential housing fill-plug". just not sure if it the "right" one.   

    But then with an appropriate gasket (copper would be a good choice) there's the old adage: "if the shoe fits . . . . . . ."   

    Scott.