489 vs. 741

You can swap in a sure-grip from any 8-3/4 case easily into your 489 case. And to note when swapping in a sure grip for an open there's no reason to have to setup gears again because your not changing the pinion depth. All you have to do is set the backlash which is a simple job with a dial indicator. I've done it a few times and it always worked fine for me. Also the 489 pinion may have the same diameter section at the front but the rear bearing section is much thicker and that's far more important because that's where the major pressure is. The pinion gear under a load is being pressed sideways against the ring gear so the thicker rear section of the 489 pinion will take much more pressure than a 741's thinner section. Nevertheless a 741 is still a very strong unit (much better than alot of guys give it credit) but if your going to run slicks and have a 489 I'd do the swap to be safe and sell the 741.