The Alfa Romeo 33 Stradale is a mid-engined sports car built by Alfa Romeo of Italy. “Stradale” (Italian for “road-going”) is a term often used by Italian car manufacturer to indicate a street-legal (usually heavily modified and/or underpowered) version of a sports car. The car was introduced at the Sport Car Show at Monza, Italy in September 1967. Only 18 have been made. The prototype (chassis No. 750.33.01) was sold to private Gallery Abarth, Japan, a magnesium bodied Stradale replica (chassis No. 105.33.12) built in late 1970s and the five concept cars are now part of the Alfa Romeo Museum. In Top Gear’s 100 Sexiest Cars list, the Alfa Romeo 33 Stradale was featured as number 15.
The 33 Stradale, first built in 1967, was based on the Autodelta Alfa Romeo Tipo 33 racing car. The car, designed by Franco Scaglione, and built by Carrozzeria Marazzi, made its debut at the 1967 Turin Motorshow.
Built in an attempt by Alfa to make some of its racing technology available to the public, it was the most expensive automobile for sale to the public in 1968 at US$17,000 (when the average cost of a new car in 1968 was $2,822). In the same year, in Italy, the retail price for a 33 Stradale was 9.750.000 lire. Just to make a comparison, the Lamborghini Miura was sold for 7.700.000 lire, while the average worker’s wage was about 150.000 lire.
The 33 Stradale is the first production vehicle to feature dihedral doors, also known as butterfly doors. The 33 Stradale also features windows which seamlessly curve upward into the ‘roof’ of the vehicle. The car has aluminium body on aluminium tubular chassis. As a result of being built by hand, each model differs from the others for some details. For example, early models had twin headlights, replaced in the last ones by single lights. The position of the windscreen wiper, and even the number of them, is another thing that differentiates each example from the others. Also the late models have vents added behind both the front and rear wheels to allow hot air from the brakes to escape.
The race-bred engine bore no relation to the mass-produced units in Alfa’s more mainstream vehicles. Race engineer Carlo Chiti designed an oversquare (78 mm (3.1 in) bore x 52.2 mm (2.1 in) stroke) dry-sump lubricated all aluminum 1,995 cc (121.7 cu in) V8 that featured SPICA fuel injection, four ignition coils and 16 spark plugs. The engine used four chain-driven camshafts to operate the valve train and had a rev-limit of 10,000 rpm. The engine produced 230 hp (172 kW) at 8,800 rpm in road trim and 270 bhp (201 kW) in race trim. The engine valves are operated via chain-driven double-overhead cams and has a 10.5:1 compression ratio. Because every Stradale is hand built and unique the power levels can vary by car, used rpms etc., for example the first production Stradale (No. 750.33.101) has factory datasheet that claims 243 hp (181 kW) at 9,400 rpm with a “street” exhaust and 254 hp (189 kW) with open exhaust.
In another break from convention Alfa used, for the first time on a production car, a six-speed transaxle gearbox by Valerio Colotti. The car has 13-inch Campagnolo-made magnesium wheels and Girling disc brakes on all four corners, the rear ones are inboard type. Despite wheel diameter is just 13 inches the wheels are eight and nine inches wide, front and rear. Suspension is like in mid-1960s race car with upper and lower control arms in front and double trailing arms in the rear, along with substantial antiroll bars.
Although the Stradale is a road car, it has some limitations which may make the everyday use slightly hard, for example missing locks and the lack of ground clearance.