I seen several gears like 373. Or 410 am new to this and the eaton lsd unit its my daily its a 2004 silveraado escb 5.3 ....it has stock 17s but will be changing to 20s or 22..thanks in advance guy..

 

You will have to deceid what gears you get on what type of driving you do and how tall of tire you have. There are some calculaters that will show your rpm at what speed in which gear

 

I have 4.10's and I run both 265/70/17 and 305/40/22 and
The tire heights are very close so the rpm is really not different. And with the 4.10 I am cruising at 70-75 at 2250-2500 rpms. I also have a slightly higher stall 2600-2800. Also I have a eaton posi unit and I'm very happy with it. Plus the nice part is those diff units are rebuild-able. Just replace the clutch pack in it. When I had 3.73 with all else listed the rpms would be the same 2250-2500 but the speed was 80 +or- 2 mph
I hope this helps