Here on the west coast VARA (vintage auto racing association) run 3 different classes of formula vee to accommodate a wide variety of vintage vees:
FV: Monoposto rules using fan shroud/generator and treaded tires up to the year '72 if I remember correctly
FV1: Monoposto rules minus fan shroud/generator and allowed use of slick racing tire (American Racers are spec slick tire) up to the year '72
*rear suspension is only defined as dual shock rear setup, so even though the D-13 has zero roll suspension if it has the dual shocks it would be allowed to run in this class
FV2: Monoposto rules minus fan shroud/generator, allowed use of slick racing tire, and monoshock rear suspension (effectively modern zero roll rear setup) up to the year '78
This allows various vees to competitively run in a vintage organization and works very well, and also solves the problem of special cases like The Sting (which would run under FV2 and would be very competitive) Maybe organizations going east should adopt a system like this? For better information on the various classes contact Kim Madrid who is the class rep for Vee in VARA her contact info is in this thread
http://www.apexspeed.com/forums/showthread.php?t=46135