Alfa Romeo GTA 1300 Junior ex Zetor Racing Team

Introducing one of the most famous legends of the Milanese brand Alfa Romeo is probably unnecessary, but still... in today's test, we have a rare opportunity to take a thorough look at and also drive an original GTA 1300 Junior version.Only 500 units of these cars—featuring bodywork made from a magnesium-aluminum alloy called Peraluman 25—were produced to meet the FIA Group 2 racing homologation requirements. Imagine the times Europe experienced back in the 1960s, compared to today, when it suffocates itself with demagoguery about emissions, carbon credits, and electromobility, legally binding its own hands and feet with bureaucratic regulations. It seems almost unimaginable now. At that time, you could just walk up to an Alfa Romeo dealer and drive home what was essentially a race car. After picking up the kids from school on Friday and grabbing groceries on the way, all you had to do on Saturday morning was wake up early, take off the bumpers, grab a helmet, and line up at the starting grid of a circuit race.Starting in 1965, Alfa Romeo manufactured the car in two specifications: initially as the Giulia Sprint GTA with a 1570 cc engine, later joined by the lower-displacement GTA 1300 Junior. The road-going version of the Giulia Sprint (which you really could buy from an Alfa Romeo dealer) was called the Stradale and put out 85 kW as standard. If a customer wanted more, they had to knock on the right door and have deep pockets. They then had the chance to have the car tuned, for example, by the legendary Autodelta in the Milanese suburb of Settimo Milanese. There, day and night under the leadership of Ing. Dr. Carlo Chiti, the most fantastic machines were born, utterly outclassing their rivals on the tracks. 

In the Corsa racing specification, the 1300 engine output reached approximately 145 hp in the carbureted version (Weber 45 DCOE 14), whereas the Stradale versions were fitted with a more civil type of carburetor—the type 18. Later, they switched to fuel injection, which allowed the power output to increase up to 160–170 hp, depending on the tuning.  Anyone who wanted to race but found Autodelta out of reach had plenty of other options in Italy at the time. Other tuning aces worked on modifying the legendary four-cylinder engine at a highly professional level. These included Franco Angelini in Rome, Conrero, Monzeglio (whose racing team had their Alfa GTAs painted in vibrant yellow with brown squares on the roof), or Santino Balduzzi from the small town of Lodi. And it is worth mentioning that if one of these geniuses laid their hands on a GTA, the customer didn't have to regret that Autodelta didn't work out. Their cars often managed to beat the factory Alfas on the race tracks.

The Stradale version featured full interior upholstery and proper 2+2 seating (which was required for homologation purposes). The Corsa version was further stripped down, equipped with a tubular roll cage, and cleared of any excess trim. The chassis was even lighter and lower. The Corsa version featured modified internal components for the gearbox and differential (hollow shafts, drilled gears), and the entire differential housing was made of ultra-lightweight magnesium to save every single gram. Racing Corsa versions from the Autodelta workshops usually featured modified ramps and clutch plate setups for a significantly higher lock-up percentage (often around 75% or more) to allow for aggressive driving on the race track. The road-going Stradale had a softer, more civilized setup suitable for public roads. The Corsa also featured a different final drive ratio in the transaxle (which was often changed depending on the specific race track), while the Stradale had universal road gearing.In 1968, three units of these racing machines made their way into an otherwise communist-locked Czechoslovakia. They were purchased by Zetor, the world-famous tractor manufacturer, which wanted to equip its newly formed ZETOR Racing team with competitive cars for promotional purposes. All three GTA versions were fitted with 1300 cc engines. Unfortunately, the chance of acquiring a Corsa version tuned by Autodelta was already a utopian dream. This was not for financial reasons, but rather because Italian patriotism offered little motivation to sell the nation's crown jewels to the Eastern Bloc. Shortly after intensive racing deployment, however, one of the three GTAs suffered an over-revved engine. Since the repair costs would have been enormous, this car became a parts donor for the remaining two. The cars very successfully participated in both domestic and international events and changed hands many times. The car we have the opportunity to see today is a very professionally restored piece, previously owned by Antonín Tvrdý Galliani, who often shared it with his Slovak colleague Marian Rajnoha in the 1970s.Its current owner, Marcel Renc, purchased it from Antonín Tvrdý in a dilapidated and incomplete state after long and complex negotiations. The car had undergone numerous modifications during the 1980s and, among other things, was missing its original engine.

Today, we can admire it in a highly authentic state, including replicas of the era-correct promotional decals from companies like Nivea and Comest. It is worth mentioning that Antonín Tvrdý, who married an Italian woman, developed excellent relationships directly with Autodelta. This gave him the opportunity to acquire some racing parts, though they were often used. Furthermore, his car went through the hands of the aforementioned Alfa Romeo engine tuner, Santino Balduzzi from Lodi.The engine in the car today is not the original one, but it is entirely period-correct. Among the biggest differences compared to standard engines—known as 'bialbero'—is its ignition system called 'accensione doppia,' which later evolved into the now-legendary 'Twin Spark' concept. Here, however, both spark plugs are of the same size, unlike the modern Twin Spark engines of the 1990s. The car is also equipped with a special rear axle modification called 'Slittone.' This system was conceived and engineered at Autodelta by Filippo Surace, though it is often wrongfully credited to Carlo Chiti. On standard Alfa Romeo 105-series road cars (including the Stradale version), the live rear axle was located by lower trailing arms and a T-shaped upper arm (the so-called T-bar) that handled lateral forces. For racing purposes, however, this setup had a distinct disadvantage—the rear roll center (centro di rollio) was too high. This caused significant body roll in sharp corners and lifted the inside rear wheel, leading to a loss of traction. Filippo Surace eliminated the standard upper T-bar and replaced it with a massive metal frame mounted beneath the differential, pointing downwards under the car. In the center of this frame (directly beneath the differential axis) was a vertical pin on which a special sliding block (slittone) moved within precise guides. As a result, the car settled into corners, and the 'slittone' stabilized the axle so effectively that both driven rear wheels remained in contact with the road. The cars began to profit significantly from this solution in the corners, and most period photographs show them with the inside front wheel lifted off the ground when exiting a turn.

Thanks to the use of lightweight body panels, the standard GTA Stradale road version shed nearly 200 kg compared to the classic steel-bodied GT. However, the Corsa version modified by Autodelta went to even more radical extremes. Technicians drilled out every unnecessary gram of metal, bringing the weight down to around 720–745 kg. Experiments were also conducted using aluminum for the chassis frame, but due to lower torsional rigidity, steel frames continued to be used even for the racing versions. Because Peraluman cannot be welded, all body panels were riveted to the frame. This is most striking in the roof crease. It is estimated that between 3,000 and 5,000 rivets were used on a single GTA, which is also why production was so expensive and slow.We had the opportunity to encounter the car at the now-traditional 'Jarní Sosnění' event at the Sosnová Autodrom near Česká Lípa. Unfortunately, the weather was not on our side, and torrents of rain began pouring from the sky just before heading out onto the track. Old racing tires and a wet track do not mix well, making it impossible to uncover the car's full potential. However, one thing was palpable from the very first meters after the start. The car felt as if it wanted to rocket forward entirely on its own. The engine protested at low RPMs, making it loud and clear that its territory lies from 4,000 RPM upwards, where it then delivered an incredibly raw pull. Another immediate observation was its featherweight nature. Even in the wet, the Alfa settled into corners completely differently than what one is used to in standard cars. That lightness is instantly apparent in every aspect. Yet, at the same time, so is its fragility. The car is actually incredibly subtle; slipping inside with a racing helmet is an almost claustrophobic experience. There are no sound-deadening materials, the windows are made of Makrolon, and you are left with purely mechanical engineering without a single trace of electronics. The interior is dominated by a racing steering wheel, which was also featured in the legendary Alfa TZ (Tubolare Zagato) and the Alfa 33. The dashboard is essentially identical to the production versions. Thanks to its low weight, the car changes direction at the slightest input from the steering wheel, giving the steering absolute precision. I have personal experience with a race-tuned and significantly lightened version of the GT Junior 1300, but here, I felt something extra. The twin-plug engine seemed sharper at higher revs with an even crisper throttle response, though the wet track unfortunately prevented me from experiencing it more deeply. In any case, a direct personal encounter with a racing version of the GTA—and a car with such a rich history to boot—meant the fulfillment of a long-held dream for me. It has remotivated me to speed up the work on my own GT so that, perhaps, we might meet on the starting grid one day. Dreams are what we are here for, after all.

The Alfa Romeo Giulia Sprint GTA and GTA 1300 Junior are legends that I will certainly want to return to in a future article, as they deserve a deeper technical analysis and a more detailed chronicle of their racing successes.

My huge thanks go to the current owner, Marcel Renc, for the opportunity to take the passenger seat. For those of you who found this story compelling, I highly recommend the book (now available in an expanded edition) dedicated specifically to this particular car: ALFA ROMEO GTA in the ČSSR. It is well worth it!

Foto: Filip Hron 2026