rear end brace?

[SS Shaun]

ok i was talking to a friend about my noise my rear has been making since day one. After talking to him he told me it sounds like my brace needed to be adjusted to hold the pinion angle better. I said what brace and so he sent me a picture


i said i have those in a box of parts but i have no idea where it goes. He told me he is not sure but it helps hold the rear in place so the pinion doesn't get out of wack. any truth to that? and where does it go on my 69 chevelle?