Did a search, but couldn't find the exact info need.

I have a friend that owns a 1993 F-150 5.0L 302 4x4 and is wanting to swap gears. Of course he's unsure what came in the truck stock. I've seen 2.73, 3.08 and I think 3.55 and 4.10, but not sure if these were all stock or if some were aftermarket.

Can anyone tell me where to locate the rear diff code at and the description of the code. I know for the 04-08 F150s they break out like this:

19 — 3.55 non-limited slip
17 — 3.31 non-limited slip
H9 — 3.55 limited slip
B6 — 3.73 limited slip

Thanks!