I believe it is the brass bushing that the front engine mount rests on. The bushing goes into a hole in the front crossmember and the engine mount stud and spring are inserted into it.
https://www.snydersantiqueauto.com/product.htm?pid=978649&cat=41692
Front motor mount under the Yoke and cross member. Just read not long ago that Ford discontinued the bushing but just used two of them on two engines.
Is this installed up from under the cross member or down from above?