Sorry it took so long Jack. Sleep and work.
I just wasted everybody's time and effort. My car has a 7.5. Ford lied to me, NAPA lied time and O'Reilly's gave me the wrong gasket. LOL 😉Just as a point of reference, All non V8 Mustangs got 7.5 axles until 2011. When the 3.7 V6 arrived it came with the same 8.8 as the V8 cars.