8 3/4 spool swap

Is the spool in a 8 3/4 the same in a 489 as 742 case? I need to go with a 4.30 that i have in a 742 w/a sure grip, and i have a 3.91(in the car now) in a 489 case that has a spool in it(need spool for 35 spine axles). I checked summit and they said its one part # for both. I just wondered before i remove the 3.91w/489 case. Basicly can i swap the spool from my 489 to a 742 case. Thanks in advance.going to drags 05/27 going to try to get this pig in the 10s