Jack,
I'm in a different class, but I never found a rule regarding SFI clutches, and I don't believe there is one.
There is a rule on SFI flywheel shields, and flywheels- no cast iron/cast aluminum flywheels are permitted. Flywheel shields are to be SFI spec 6.1, 6.2, or 6.3, depending on the application.(3.0 in rule book)
Contact Lee Kennedy, -He's the car tech committee chair, and over the special construction catagory.-techchairs@scta-bni.org
Good luck!