Cost for A Body 8.75 Rear End

it’s a 1969 dart custom so I’m not sure where that puts me lol

So keep in mind that A-Body with BBP axles, and any B-Body rear is going to widen the track as well as any 73-up from 4.5x5 disc brake swap so keep wheel offset in mind. 67-69 Darts don't have near the room as Dusters, Dart Sports, and 67-up Barracudas have. So plan what rims you want to run and fit them accordingly. Lets just say Zero or Negative offset will not work here which it what you will find the most of for these cars.