As mentioned, there are two major players in the Foxbody supercharger world. Vortech and ProCharger are the big dogs, and both companies offer great centrifugal kits.
Vortech: Vortech has two offerings. Their entry level ‘Street Boost’ kit features their V-3 self-lubricating supercharger, capable of 5-6 PSI of boost. Included with the kit is a fuel management unit and mounting hardware. If you’re looking for bigger power, consider their next level up, featuring their V-2 SQ Si trim charger, ribbed to produce between 8-10 PSI at wide open throttle. This kit also includes a fuel management unit with a high flow fuel pump, as well as a digitial MSD ignition box to help prevent pinging. On a stock engine, the basic Street Boost kit is good for a gain of 50 HP and 75 ft-lbs of torque. The V-2 kit will net in the neighborhood of 100 HP. These numbers don’t sound like much, but keep in mind they are for a STOCK engine. Expect bigger gains if your engine has been modified to breathe better (ex: cylinder heads, intake, camshaft).
It is interesting to note that Vortech says their Street Boost kit does not need an intercooler, nor will adding one net any additional power. Furthermore, Vortech states that a standard bypass valve is necessary for systems that exceed 6 PSI of boost and a MaxFlo racing bypass valve for 10 PSI and more.
ProCharger: Like the competition, ProCharger offers two kits. Both kits feature their P1-SC self-contained supercharger, a 2-core air-to-air intercooler, bypass valve and high capacity fuel pump. Of course the mounting hardware is included too! Their first kit comes with an 8-rib pulley whereas the more expensive second level is equipped with a 12-rib pulley.
A great feature that both companies offer is that some of their units are self-contained, meaning there is no need to tap your oil pan and run a line to the supercharger – they are self-lubricated.