Not sure which Eaton supercharger is being used in these kits. But....
Depending on the supercharger, assuming 195hp 3.9/4.0 engine:
Eaton 90 - 520cfm at 10 psi @ 12000rpm @ 80 degrees F inlet, 240 degrees F outlet ~ 266hp theoretical maximum.
Eaton 62 - 450cfm at 10 psi @ 14000rpm @ 80 degrees F inlet, 240 degrees F outlet ~ 230hp theoretical maximum.
I doubt given the age of these things that they are 112's.
Note that intercooling the charge air down can increase the horsepower dramatically. Reducing the outlet temperature to 150 degrees boosts theoretical power to 315hp and 272hp respectively.