74 dart drum sbp to lbp disk
Exactly! :D
And, a set of bolts to mount them up. They'll be the same diameter and thread as the ones attached to the 5th Ave ball joints, but they'll need to be about 3/4" longer because the A body lower ball joints are not threaded like the 5th ave pieces are.
Also, the stock bolts that served this purpose have a thinner head. I would just buy a set of grade 8's at the hardware store, but keep in mind you may need to grind the heads thinner to get enough clearance on the rotor. Or, find a stock set of lower ball joint bolts for a 73+ disk brake car. Not a big deal, but do a test fit and check clearance if you go the grade 8 route.
**EDIT**
Nevermind, saw that you have a SBP disk brake car already. Not 100% positive, but I believe you may be able to use your old lower ball joint bolts. The ball joints themselves are different, but the bolts should be the right length. I've never had a SBP disk set up, so I'm not sure if they're the same diameter though.