WANTED 8.25 Cop car differential locker

Got a buddy that bought the car back that I originally bought off him. He's surprised me by doing quite a bit of work on it. I first heard that he wanted to put a 9" ford under it. He doesn't have that much power in it now. He's wanting a lower gear. So I'm trying to help him find a good used cop car " Factory " suregrip from a Diplomat. Looking for something that can if necessary go up to a 4:10 ratio. Like to find, for him, a 3:23 - 3:55 complete, ready to install.

Fella just listed a (mostly) complete AHB diplomat for $900; but it’s down in Mustang, Oklahoma. Someone already swapped the header panel on it, as good as a part car now for a rear end swap. But it will likely have a 2.94 or worse

Get one from a Jeep…

or dodge dakota