I have this official GM parts master cylinder cap that I bought for my 72 Supreme and for some reason it must not have been quite the correct fit, because when I installed it, it leaked around the gasket.

At any rate, I have no use for it. I'm not sure of other applications, so do your research. Part # is 12341906

No scratches or defects, just needs a little cleaning.

Gasket not included.

First response gets it, so good luck!