The Fiat 850-based Abarth OT Coupes

Whilst the Fiat 600 had provided a good chassis/mechanical basis for the scorpion-badged Grand Tourers of the early Sixties, it had been necessary for Abarth to create bodies of a style appropriate for the GT designation.  These cars reached their performance and aesthetic high point around 1963/4 with the 1000 Bialbero, alongside the Simca-based 2000 GT.  Just at that time (March 1964) Fiat introduced the 850, a model family that not only offered new performance possibilities with the enlarged engine capacity, but also a ready-made suitably styled coupe body.  Abarth was quick to get to work on the 850 with a 60 bhp Berlina OT (Omologata Turismo) 982 cc version in October.  The Coupe was introduced by Fiat in 1965 and that September Abarth launched its OT 1000 version.  The enlarged Tipo 202 engine was good for 60-65 bhp.

Abarth’s considerable achievement in taking class ‘World Championships’ in the period 1962-67 was in the main due to the performance of the 1000 GTs, Simca platform GTs, 1000 Berlinas and 1300 OTs.  The OT 1000 Coupe was not favoured for international race participation but was successful from the outset as a customer racer for national events.  The OTR version appeared along with the OT in autumn 1965.  The car in standard form (74 bhp) was suitable as an ‘off the shelf’ race car or, uprated with factory options, in enhanced competitiveness trim, (95-105 bhp).  The engine was based on the Tipo 200 but with a new ‘radiale’ head and improved cooling thanks to a nose-mounted radiator.  The form of the combustion chambers in the radiale engine is apparent in the photograph below – two overlapping hemispherical voids which, together with individual, separate, exhaust ports and twin Weber 40 DCOE carburettors, made for highly efficient atomisation, induction and gas flow characteristics.  As a result, the engine was considered to be ground-breaking in developing 100 bhp from a sub-1000 cc capacity.  The performance was all the more remarkable since the engine was capable of running at over 7000 rpm despite having pushrod actuated valve gear.


The adoption of the forward position radiator dictated the need for redesign of the car’s front panel to provide an air intake aperture.  The resulting grille, script and central badge lent the nose a distinctive and aesthetically pleasing character.


However, exploitation of the new engine was soon compromised.  In the U.S., the motorsport-governing Sports Car Club of America, took against the OTR and ‘banned’ it, believing the extent of modification to be extreme and outside the spirit of the rules of their relevant racing classes.  This significantly constrained sales potential in such an important market for Abarth.  Accordingly, it is generally held that less than forty OTRs were built by Abarth.  The Sixties were notable for the instability of racing class definitions and related homologation rules.  Abarth was frustrated in being unable to gain Group 2 homologation for the radiale cylinder head, only able to achieve this in 1970.  For Abarth it was important to have models which were ‘legal’ for as many classes as possible.  This gave rise to a further 1000 Coupe variant – the OTS, utilising the OTR body but powered by the standard cylinder head engine (67 bhp).  This was successfully homologated in 1966 for FIA-governed GT racing.  Alongside, a higher powered (90 bhp, achieved with carburation/manifolding upgrades) OTSS version was also offered.

1966 was a hectic year at Corso Marche, as indicated by this list of newly emerging variants on the Fiat 600 platform: OT 1600 Prototipo; 1000 TC Berlina Corsa; OT 2000 Coupe America; OT 2000 Coupe; 1000 TC Radiale Berlina; OT 1300 Sport; OT 1600 Coupe Prototipo.  And there was one more, which is especially relevant to this post – OT 1300/124 Coupe.  Unveiled at the Turin show in November, this was somewhat unusual in comparison with the 1000 versions since the engine was only mildly modified by Abarth.  However, the larger capacity of the 124 engine, oversquare bores and raised compression ratio enabled a relative unstressed output of 75 bhp.  Both front and rear suspensions were also upgraded whilst the ride height was lowered and the track increased.

Abarth won the last of its 6 consecutive FIA championships in 1967 with the OT 1300 – however, to avoid possible confusion, it should be understood that this car was Simca-based and featured a Sibona & Basano-made fibreglass body, unrelated to the Fiat 850 coupe shell.

In 1968 Fiat facelifted the 850 Coupe, adding ‘Sport’ to the model designation.  From a mechanical viewpoint, the main upgrade involved the engine, capacity being taken out to 903 cc.  Cosmetically, the most notable changes affected the front end, incorporating 4 lamps, repositioned indicator lamps and reshaped/front panel featuring a ‘v’ shaped chrome embellisher.


An Abarth OT 1000 version of the 2nd Series Coupe was launched in 1969 and for some time this was in production alongside a similarly updated OT 1300/124 Coupe, ending in 1970.



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