Upgrading diff/4.10 gear swap

[Rick1991]

I'm wanting to get 4.10 gears into my 91 Silverado and while I'm doing that I might aswell diff while I'm at it. I don't want to don't want to do the 14 bolt swap either.

So a few questions:

How hard is it? Is it something I can do myself or should I be paying someone?
Is my diff a 8.5" if its a g80?
Which diff and gear set will be strong?

Would these be good? My truck is lowered (hense no 14bolt swap) and making 402WHP, and it will only go up from there so I want to do it right the first time.
http://www.summitracing.com/int/parts/aub-542052/overview/year/1991/make/chevrolet/model/c1500
http://www.summitracing.com/int/parts/rmg-sgm8506/overview/
http://www.summitracing.com/int/parts/rmg-8310211/overview/

 

[df2x4]

I would definitely pay to have it done, personally. It'll take a good shop the better part of an afternoon to get it done right. I'd also go with an Eaton TrueTrac instead of that Auburn Posi, especially in a lowered truck. They're just so smooth, you never feel them do anything. They just work. From what I've read and experienced (although the one I drive regularly has only been in service for a few months now), Eaton products are extremely durable and reliable. The TrueTrac is a helical gear posi instead of the typical clutch style. They seem to be pretty well reputed. You're on the right track with the Richmond gears, I've had good experiences with them. Might want to check who makes the bearings in the install kit though, I hear Timken is the way to go. If you do end up going with an Eaton carrier they require some different bearings in the kit anyway. Here's a Motive install kit designed for the 8.5" Eaton carriers. (With Timken bearings, I confirmed with Motive on the phone)

http://www.summitracing.com/parts/mgr-r10remkt

As far as the G80 code, that just means you have the factory locker. Applies to all the rears. If it's a 10 bolt, it's the 8.5".