Wheelbase is 195 in (4,953.0 mm) and dry weight 409 kg (902 lb); top speed for the larger model was claimed to be 150 km/h (93 mph).

[1] In 1956 Abarth presented twin concept models, based on the Fiat 600 chassis and its 747 cc (45.6 cu in) engine.

Abarth 215 A Coupé was a closed variant presented at the Geneva Motor Show and the following open-top spider had its first premiere in Turin.

Siata's own 600-based "Amica" design and 735 cc (44.9 cu in) engine conversion was thus marketed as the Siata-Abarth 750 during those years, but there was little to no actual Abarth involvement with these cars.

Fiat delivered these cars incomplete, to make it easier and more cost effective for Abarth to carry out their performance modifications.

Sharper cams, lighter flywheel, a bigger carburetor, and myriad other traditional tuning tricks were employed; as a result power nearly doubled, up from 21.5 to 40 CV (16 to 29 kW).

[4] The all-aluminium bodywork has Zagato's famous "double-bubble" design and Abarth's tuned derivazione engine with 43 CV (32 kW; 42 hp).

By the time of the appearance of the Abarth Zagato Record Monza 750 Bialbero, the bodywork had been unified into a separate model with a rather large hump on the engine lid, made necessary by the taller twin-cam motor.

)[5][6] The 750 GT Bialbero model appeared at the 1958 Turin Auto Show; along with various alterations to the bodywork it has the new twin-cam engine with 57 CV (42 kW; 56 hp) at 7000 rpm.

This, by necessity, made the Bialbero engine quite tall, necessitating sizable bulges and bumps in the bodywork on lower designs like the Zagato or various Spiders.

[9] 750 Bialbero-equipped Fiat-Abarth Zagato Record Monzas featured a lower roof with no bubbles and one single centered air scoop on the engine lid.

[13] To suit newly reshuffled Gran Turismo racing categories, a 698 cc (42.6 cu in) version was introduced at the 1959 Turin Auto Show.

[18][19] It uses the Fiat 600 bodywork with some modifications, most notably a boxlike structure ahead of the front bumper which held the engine's oil cooler.

The engine is a four-cylinder model based on a Fiat unit, with 847 cc capacity and 52 CV (38 kW; 51 hp) CUNA rating.

This culminated in a famous dispute with SCCA authorities in the USA when Alfred Cosentino (FAZA) was banned from running his 1970 Fiat Abarth Berlina Corsa 1000 TCR "Radiale" engine because his car was faster (mainly in wet conditions) than many of its V8-powered contemporaries.

The SCCA authorities dictated FAZA and Cosentino be forced to use an earlier, non-Radiale, engine design from the 1962 model in their cars.

The first Fiat 600-based Abarth to be fitted with the larger 982 cc development of the 600 engine was the Zagato-bodied Berlinetta, similar in appearance to the 750 and 850 Monza models.

[21] A bewildering variety of slightly different bodystyle elements appeared over the years, with covered and uncovered headlights, different engine lids, taillights, and window arrangements, as well as a later long-tailed design which also received a longer nosecone.