1966 FIAT 500(F) Giannini modifed
(Abarth competitor)Giannini was (and still is) an Abarth competitor
Absent additional provenance, this is likely a 500F with aftermarket Giannini tuning equipment (rather than an actual "production" Giannini).
Rear engine, air cooled, 2 cylinder, 18hp 500cc (likely 35hp, 650cc+ in this car). Slightly smaller dimensionally than a Mini, but at around 1200lbs, a couple hundred pounds lighter.
Former NASCAR Graphics are a custom wrap (car was used for advertising *in* an office); too bad it wasn't a "vintage rally" wrap!
(former NASCAR Graphics were a custom vinyl wrap for advertising)