The GTA was actually the work of Orazio Satta Puliga, the brilliant engineer that headed Alfa Romeo at the time. He took the most iconic of all Alfas, the Bertone / Giugiaro GTV and started by replacing the heavy steel body panels such as bonnet and boot lid, with lighter aluminium alloy parts. Therefore the “A”, for Alleggerita or lightweight in Italian, in GTA. He then send the shells to Autodelta, Alfa Romeo’s racing wing, for Carlo Chiti, it’s boss to install the race proven double spark headed engines, previously used in the TZ2s, modified suspension and other bits, ( that included cam cover, front crankcase cover, bell housing and rear gearbox plate, that were made in magnesium alloy,) for it to be eligible to compete in the two year old, Group 2, European Touring Car Championship (ETCC), that had proven extremely popular with the man on the street, that could associate the racing cars with his everyday transport.
One item that helped with this, was the fact that the bodies measurements remain untouched, in accordance with the strict rules, that forced cars to use road tyres. The cars were introduced in 1965 and promptly not only won the first race of the inaugural Trans –Am series in the USA, (driven by Jochen Rindt) but also the championship, racing mostly against 5 litre American big bangers. The 1570 cc GTAs were entered in Division 2 for cars up to 1600cc. The car to beat was the Lotus Cortina, but soon they were retired by the GTAs, that is claimed to have won 300 races in 1966 alone. Concurrently to the Gr 2 GTAs, Autodelta also built GTAs for the British, Belgium and French Group 5 championships. But if the Gr 2 cars kept their standard bore and stroke, (78 x 82) the Gr 5 cars, named GTA –SA for their oil driven twin superchargers, were equipped with over square engines of 86 x 67,5 mm. The Junior is born. In 1968 Alfa Romeo introduced a new line of models powered by 1300 engines and named them (GT, Spyder, Zagato, etc) Juniors.
AUTODELTA GTA-SA Supercharged
AUTODELTA GTA-SA Supercharged Engine with 2 Oil compressor
At the same time the ETCC rules changed allowing Gr 5 cars to compete with Gr 2 vehicles. It meant that mud guards could by widened and racing tyres used. The original GTA, that Carlo Chiti in the foreword to Tony Adriaensen’s masterpiece book “Alleggerita” , said “was a car that really didn’t have anything special”, suddenly grew muscles and broad shoulders, with the addition of wide mudguards riveted over the old ones, to accommodate wider wheels. In that same year, Autodelta introduced the GTA Junior powered by a standard engine bore of 78mm, but with the stroke of the SA engine, of 67,5 mm. The car was entered in the Division 1 now for cars up to 1300 cc and for the next few years, until 1974, when BMW and Ford forced the FIA to abolish the division*, had no competitors. ( continue )