7 1/4 to 8 1/4

you need to make sure you get the u bolt shock brackets and if possible the u bolts as the 8 1/4 is different than the 7 1/4. If the car you are looking at still has the rearend in it you can just take them off that car. If not the 8 1/4 stuff is the same as any 8 3/4 a b e or c body i believe. You will also have to shorten the driveshaft for the 8 1/4 other than that it will swap right in only other difference i can think of is e brake cables 71 down had different than 72 up so if your duster is a 70 or 71 you may need different e brake cables I hope i didnt forget anything but if i did im sure someone will finish up for me Good luck Justin