I'm not an expert on rearends but I did talk to one today actually.He said the 742 is the most desirable and uses the same bearings as a dana. Right or wrong?
casting year body pinion
741 64-74 ABCE 1 3/8
742 59-68 BCD 1 3/4
489 69-74 ABCE 1 7/8
Now if you do some math and figure the years of some of the big HP cars out there,you can see that they used the 741&742 castings and the dana,s.If you can get a 489 case,yes do it,but a 741 &742 case,s are behind big heavy cars and big motors too.If a 489 case is behind a stock and modified hemi automatic car,any of the cases are good for street use.Now you remember the cars came with,413,426 wedge,hemi,s 383/440 and they used these case,s, so there is know need to worry,mrmopartech