CaptDistraction

I need to move the axle-vent on my GT to the boss cover I've installed (which just has a bolt with a rubber washer plugging it for now), but was curious if anyone had a part number or spec on what ford uses to plug the threaded hole in the axle-tube.

Might be a reach, but figured worth asking. Searches were either too generic or didn't lead anywhere other than the possible thread spec.