The wagons do not have many heavy duty parts. The only parts that are heavy duty are the tow package springs. Other than that, the parts are the same as a standard Caprice with 11 inch drums.
The heavy duty brakes for the police cars and Fleetwood commercial chassis. Front only. The 5/8 inch ball joints are on the 9C1, and require different spindles.
The rotors are the same for all B bodies. Rear brakes are 11 inch drums. The 9C1 may have different brake pads.
If you relate the type car you have to the parts seller, you should get the correct part, unless the seller makes a mistake, and gets the wrong part, or is stupid.
Rock Auto allows you to pick the part from their list, and their list for a given car is just for that car.
1991 OCC 461 (.030 over 454) BBC, 3.23 posi, flash to pass, drop spindles & springs, Impala rims, Hydroboost, Recaros, MOMO/wood SW w/QR, custom wood shift knob, Pioneer DEH P77DH
1992 OCC now with 5.7 tbi, DEH P77DH
For a parts list, check https://www.impalassforum.com/vBulle...ion-parts.html
The confusion I had after buying my wagon is the listings aren't 100% correct.
They offer/show the larger HD balljoints for example, when in fact the car did NOT come with them.
This is pretty much across the board, online & parts stores.