FWIW I was revisiting the US Car tool page, and if you zoom in on this photo you will see that they leave what's left of the old flange in place, so per earlier posts, they must be Chevy guys.



My car was done by a one-eyed fabricator with an axe back in the 70s, so I'm investigating the best way to improve things and am considering that kit but am not sure it will work, since the inner was originally cut different than US Car Tool recommends. May end up having to replace the inner too, to make it right again.