ASA (Autocostruzioni Società per Azioni)

The ASA 1000 GTC was a sports racing car built in 1963 by Giotto Bizzarrini and based on a production 1000 GT. The car was developed under a newly-founded Società Autostar workshop. The body was designed and built by Piero Drogo's Carrozzeria Sports Cars. The engine had its displacement reduced to 995 cc to meet the under 1.0-litre racing classification. The tubular chassis with aluminium body saved the weight to a total of 590 kg (1,300 lb). Bizzarrini and Drogo also built a larger displacement car called 1300 GTC with 1.3-litre engine that debuted at the 1966 Trento-Bondone Hill Climb.

The ASA Berlinetta 411 was the competition version of the 1000 GT Coupé, introduced at the 1965 Paris Motor Show.[3] It used the engine from the 1000 GT enlarged to 1,092 cc (66.6 cu in) by increasing the cylinder bore from 69 to 71 mm. This engine produced 104 bhp (78 kW) at 7500 rpm. The Berlinetta 411 had a lightweight all-aluminum body and plexiglass windows, resulting in a dry weight of 709 kilograms (1,562 lb) compared to the regular 1000 GT's 780 kilograms (1,720 lb). Other modifications included wider tires and a competition gas filler. The exact number produced is unknown. Two competition 1000 GTs were entered in the 1965 Targa Florio. They placed 17th and 22nd overall, 3rd and 4th place in the 1000-1600cc prototype class.

ASA also manufactured four fiberglass-bodied competition cars called the RB613 or Roll Bar 1300. These featured a more aerodynamic body designed by Luigi Chinetti Jr. and manufactured by Carrozzeria Corbetta. The chassis had an integrated roll bar, the source of the "RB" abbreviation in the name. The engine was a 1.3 liter straight-six, the design based on 1/2 of the Ferrari 250 V12. Two ASA RB613s were raced at the 1966 24 Hours of Le Mans, one an ASA factory entry and one entered by Luigi Chinetti's North American Racing Team. Neither car finished the race. NART entered another RB613 in the 1967 Daytona 24 Hours. Driven by Suzy Dietrich and Donna Mae Mims, the ASA finished 24th. The same driver team again drove the ASA for NART in the 1967 Sebring 12 Hours, finishing 25th.

A similar 1.8 liter 4-cylinder RB618 or Roll Bar 1800 competition model was developed for the American market. The quantity produced and racing history of this model is unknown.