Front End/Rear End
 

I know someone has probably asked the question before but I could not find the response. Here is the rundown:
I just bought an 87 K5 as a project truck for my daughter and I to work on. The front and rear end are geared differently. I would like to do swap out one or the other, what resources can I use to reference the repair? Is there generally a preference to which I would switch? The truck will be for her upon completion and may do some light off road work but nothing too crazy (South Texas is flat as a pancake).
It is our first build, but I have a decent amount of tools, patience and time...not to mention I am mechanically inclined.
Thanks in advance!

Id do the rear before the front if it was me. For now you need to find out what gear ratio either one is.

google " gear ratio counting teeth" and read into how to figure it out.

There should be a sticker in the glove box,or somewhere. it has a bunch of 3 letter/digit codes on it. find any of em that has the first letter g. itll be like gu1,gu2,gu3 etc. post back. Problem is its hard to tell which of the 2 diffs has been swapped unless you can tell by worn nuts,bolts,and gouges. etc

Agreed, rear axle is easier. I would chose the lowest geared, and replace the other.

The code in the glove box reads GU6.

3.42 .....

yep 3.42,if you have "g80" beside it you also have a locking diff,it was a option.