Rear-end weight difference

That's what I'm afraid of. I'm gathering parts to swap out my 2.76 ratio 7.25" for a 3.23 8.75", but I'm worried that most of what I gain from gearing I'll loose from added weight...

Eventually I plan on swapping my A-904 (100 lbs) for a T-5 (75 lbs), but that's down the road.