All of the 5.0 Explorers came with the LS 3.73's, everyone reports that. So you just need to replace the clutches in it, and do new axle seals and bearings, parking brake pads while in there too.
I got a LS clutch kit from an Advance Auto last Spring to do mine, I forgot the brand now. I found it while searching the clutches, I'll get to doing mine this year. This kit had more clutches then a the normal/OEM six(three per side). Most people know that you can install four per side if you arrange the clutches friction/steel etc, and not two steels together like stock. I did that with two OEM kits in my old 93 diff, it lasted longer than the stock six clutch setup. This new kit I got I think had eight in it, an extra one per side. So at $85ish, it was cheaper than some of the OEM kits($80-$130), and it only takes the one kit to get the added clutch pair.