[Bret Kepner]

Actually, it's plainly posted in the rules under INDUCTION SYSTEM, Supercharger:

The ADRL Technical Services Department maintains a list of OEM superchargers originally offered for production vehicle use. Supercharger eligibility for the SCS is not guaranteed and constructors should consult with the ADRL Technical Services Department prior to committing to a specific supercharger model. At present, the 4.0 liter, (244.20 cubic inches), displacement Whipple unit is not eligible for SCS participation.