I posted this on the explorer side and realized that there aren't any Ranger guys chiming in... so I decided to post it here too for all my fellow Ranger drivers :)
So here it is... the most complete HOW TO for supercharging your 4.0L Ranger! If you obtain a Moddbox Installation kit and any Eaton M90 supercharger (89-95 either style inlet... you can opt to buy one with warranty in the kit), just follow the following instructions and you're good to go. No tune required. 100% bolt-on mod. You can get your installation kit here:
ModdBox - Engineering your driving experience
I've also decided to post the "final result" first. If you like it.. proceed to read the "how to".
Here's the Dyno. 215 hp & 237 lbft at the rear wheels...