The 33's low-slung, race-bred mid-engine chassis provided an ideal platform for advanced design experiments: some of these creations would end up having a lasting impact on the evolution of car design, while others were soon forgotten once the motor show's spotlights switched off.
The gorgeous Alfa Romeo 33 Stradale from 1967 is rightfully considered among the most beautiful and desirable automobiles ever produced.
Yet, despite the model's legendary status today, just 13 examples were ultimately constructed between 1967 and 1969, including two prototypes. Finding itself sitting on five more unused 33 Stradale chassis, Alfa Romeo lent them to Italy's most preeminent design houses of the day to be transformed into spectacular motor show prototypes.
One: Bertone Carabo
Penned by Marcello Gandini for Bertone and first displayed in October 1968 at the Paris Motor Show, the Alfa Romeo Carabo arguably changed the course of automobile design forever.
With its revolutionary wedge shape, sharply truncated rear end, and origami-like surfaces, it pioneered the trends that would dominate car design during the 1970s and into the early 80s.
The name Carabo derives from a species of ground beetles called "Carabus Auratus," whose iridescent green color with golden reflections inspired the paintwork of this one-off Alfa Romeo, which also marked the first appearance of the dramatic "scissor doors" Gandini then implemented three years later in the Lamborghini Countach and have characterized several other Lambos ever since.
And, much like the Countach, the Carabo still looks otherwordly over five decades from its first appearance.
Although it's based on a 33 Stradale chassis and was presented barely a year later than Franco Scaglione's curvaceous original, these two objects seem to hail from two different planets altogether, which goes on to show just how quickly automobile design was evolving in those days.
Even though it's not a production model and was never meant to be, the Alfa Romeo Carabo can be considered one of the most influential automobile designs of the 20th century, and it rightfully occupies pride of place in Alfa Romeo's historical museum.
Two: Pininfarina P33 Roadster / 33 Spider "Cuneo"
The second prototype based on an Alfa Romeo 33 Stradale chassis broke cover barely a month after Bertone's landmark Carabo and was presented by the rival firm Pininfarina in November 1968 at the Turin Motor Show.
Styled by Paolo Martin and simply known as the P33 Roadster, it featured a somewhat unconvincing mix of subtle curves with sharp surfaces, plus a large spoiler positioned right behind the open two-seat cockpit.
However, even Pininfarina evidently wasn't happy with how the car was received, as it reutilized the same chassis for a new prototype that was then presented at the 1971 Brussels Motor Show.
Penned by Leonardo Fioravanti and presented simply as the "33 Spider," it's been since known by the nickname "Cuneo," which is the Italian for "wedge," for rather self-evident reasons.
Arguably the purest, most uncompromising wedge shape ever seen in the history of car design, Pininfarina's "33 Spider" prototype belongs to the Alfa Romeo museum's collection and often serves as a placeholder when the museum's 33 Stradale goes out for display somewhere else.
Three: Pininfarina 33 Coupé Speciale
Pininfarina presented another striking prototype based on an Alfa Romeo 33 chassis at the 1969 Turin Motor Show.
However, the so-called 33 Coupé Speciale wasn't an original design but rather an adaptation to the Alfa chassis of a design from Leonardo Fioravanti built on a Ferrari chassis: the P5, which had been very well received by the public and critics alike at the 1968 Geneva Motor Show.
Among those who appreciated the P5's lines, there was Alfa Romeo's president Giuseppe Luraghi who, upon learning that Enzo Ferrari had no further plans for it, tasked Pininfarina with adapting the P5's design to a 33 chassis. Although there allegedly were intentions for a small production run, reflected in the more traditional front and rear lighting arrangements compared to the original Ferrari prototype, the pale yellow 33 Coupé Speciale ultimately remained a one-off.
However, one thing from this striking prototype eventually reached production: its paint color became the aptly named "Giallo Prototipo" available for the Alfa Romeo Spider between 1970 and 1977.
Four: Ital Design Iguana
But the 1969 Turin Motor Show saw the debut of another prototype based on the 33 Stradale chassis, the Iguana from Ital Design, which had been founded by Giorgetto Giugiaro and Aldo Mantovani a year prior.
Arguably the most influential automobile designer in history, I've always admired Giugiaro's work and forever will.
However, I must admit I struggle to appreciate the Alfa Romeo Iguana, not just because of its truly awful metal flake paint finish.
In my view, the best part of the Iguana is the glazed roof with brushed stainless steel pillars. Still, overall the Iguana doesn't seem to have stood the test of time as gracefully as Gandini's Carabo has, proving that sometimes even the greatest minds can have a bad day.
Five: Bertone Navajo
Speaking of geniuses having an "off" day brings us nicely to the last dream car based on the underpinnings of the 33 Stradale: the Bertone Navajo, which debuted in March 1976 at the Geneva Motor Show.
By then, the Alfa Romeo 33 Stradale was already history, but that didn't stop Bertone's protegé Marcello Gandini from once again pushing the boundaries of automobile design.
However, the result this time is arguably much less successful than the Carabo from eight years earlier.
With its cartoonish stylistic excesses and almost "brutalist" surface treatment, the Navajo looks more like a sci-fi movie prop than the product of Italy's finest design tradition.
Like all the other prototypes I previously mentioned, the Navajo resides in the Alfa Romeo museum's collection, but it spends most of its days in storage rather than on display.