[7] The Alfa Romeo Spider was based on Giulia mechanicals, including its Alfa Romeo twin cam inline-four, independent front and solid axle rear suspension, and unibody construction, incorporating the relatively new principles of crumple zones into the front and rear.

As for its predecessor the Giulietta Spider, the Italian firm of Pininfarina was responsible for the design, manufacturing of the body, and final assembly.

Centro Stile Alfa Romeo and Bertone presented a proposition for a two-seater sports car that was developed between 1962 and 1963.

[12] Despite being an aerodynamic coupé with prominent fins on the rear, and a futuristic all-plexiglas greenhouse and front wings, the Superflow already showed the overall body shape of the future Spider and the scallops on the sides.

[13] The Spider was launched at the 36th Geneva Motor Show in March 1966,[8] and together with the Giulia Sprint GT Veloce tested by the press at an event organised in Gardone Riviera.

[9] To choose a name for the spider Alfa Romeo announced a write-in competition, offering an example of the new car as a prize.

[15] Over 100,000 ballots were sent in, the great majority from Italy; the winner was Guidobaldo Trionfi from Brescia, who proposed the name "Duetto" (duet).

[15] However it could not be officially adopted due to trademark issues: the confectionery manufacturer Pavesi had launched on the market in 1965 a chocolate snack called, indeed, 'Duetto'; the Court of Milan ruled that Pavesi, having already registered the name, had exclusive rights to it, thus the car was named simply Alfa Romeo Spider 1600.

[22] Modifications were also made to the suspension, brakes, electrics, 14" wheels and 165HR14 Pirelli Cinturato CA67 tyres, though the car looked effectively the same.

Visible differences were limited to the rear-view mirror repositioned to the door, and badging on the tail, which read "Alfa Romeo" and "iniezione" (injection).

[23][24] From a mechanical standpoint the Junior differed from the 1750 only in engine displacement and output, while inside it lacked some features of the pricier model: namely opening quarter lights, centre console, and the three-spoke wood rimmed steering wheel, replaced by a two-spoke plastic rimmed one.

From outside the Junior version could be recognised by its black-coloured lower front bumper and absence of plastic headlamp fairings.

Numerous other small changes took place both inside and out, such as a slightly different grille, new door handles, a more raked windscreen, top-hinged pedals and improved interior trim.

Based on the Spider, it featured a Porsche style solid rear window and black lift out GRP roof panels.

Also, between 1974 and 1976, the early-style stainless-steel bumpers were discontinued and replaced with black, rubber-clad units to meet increasingly stringent North American crash requirements.

The Spider received a further styling revision in 1983, with introduction of black rubber front and rear bumpers, a front bumper incorporating the grille, a small soft rubber spoiler added to the rear kammback, and various other minor mechanical and aesthetic modifications.

The Quadrifoglio Verde (Green Fourleaf Clover) model was introduced in 1986, with many aesthetic tweaks, including sideskirts, mirrors, new front and rear spoilers, hard rubber trunk mounted spoilers with integral third stoplight, unique 15" alloys and optional removable hardtop.

It was otherwise mechanically identical to the standard Spider Veloce model, with a 2.0 L (1,962 cc) DOHC 2 valves per cylinder four-cylinder engine, fuel fed by twin two-barrel 40DCOM4/5 Weber carburetors in Europe producing 128 PS (126 bhp; 94 kW) at 5400 rpm and 178 N⋅m (131 lbf⋅ft) at 4000 rpm of torque; while in North American models retained the Bosch L-Jetronic fuel injection introduced for the 1982 model year except that the VVT mechanism was now L-Jet activated and five-speed manual transmission.

Only minor changes occurred from 1986 to 1989, including new paint colors, the addition of a center high mount stop lamp (CHMSL) midway through 1986 for North American models, a move away from the brown carpet, and new turn signal levers.

To comply with federal passive safety standards, a subset of Model Year 1988 examples featured automatic seatbelts with the shoulder belts' internia reel retractors mounted behind and between the front seats, and routed through guides mounted on the inboard shoulder of the upper seat backs.

Series 4 launched in 1990, with Bosch Motronic electronic fuel injection,[3] full-width body-colored plastic bumper fascias, an electric cooling fan, full-width rear taillights, on-board diagnostics an optional automatic transmission—while eliminating the much criticized front under-bumper and rear trunk-lid spoiler of previous series.