Help: Chevy truck rear end question

My buddy’s rear end went kablooie in his 96 Chevy 1500 with the Z71 package. It’s got a 350 and auto trans.

He found 2 axles pretty cheap, but both are out of 4.3L cars. I don’t know shit about Chevy truck rear ends. Was there a difference between the 4.3L and 5.7L rear ends? Also I know gear ratios are different normally in autos and manuals, so which one should he get if so? Thanks guys

$100 4.3L automatic transmision axle

$150 4.3L manual transmission axle

I think the Z71 package might include a different rear end, wider or something.

Youll need to get one with the same gear ratio as whats in it because the front and rear gear ratios need to match in a 4x4.

Keep looking because theres millions of these trucks in junkyards.

he needs to get the same ratio rear and what not if its 4wd .the rpo code is in the glovebox or look at the rear diff and see if the tag is still on it the z series truck have a heavier duty rear and a posi get the gear ratio or call the dealer wit the vin and they can tell ya what ratio and what not it has