With an eye on replacing the Maserati A6G 2000 road car, the Orsi family explored various options during the second half of the 1950s. One of them was a relatively compact machine, powered by a 1.5 litre four cylinder engine and dubbed the 150 GT. Eventually, the larger and more powerful 3500 GT received the nod, retiring the single 150 GT development prototype built to a corner of the factory.
The life of this unique machine actually started several years before it took its final form, which is illustrative of how tight resources prompted manufacturers to recycle existing components where possible. The chassis was laid down in 1954 for the A6 GCS/53 sports racer used by works driver Luigi Musso. He campaigned the six cylinder machine throughout the year on his way to becoming Italian Champion in the 2-litre category, finishing third overall in the Mille Miglia and first in class in the Targa Florio.
At the end of the year, Maserati could not sell the car because, for a variety of reasons, it had received the same chassis number as the A6 GCS/53 used by Musso in 1953. Instead the car was stripped and served as the third prototype for the upcoming 300S sports racer. Re-numbered '003', the chassis was lengthened and fitted with a 250F derived six cylinder engine, bigger brakes and transaxle gearbox. Throughout a testing period, the chassis was gradually modified, making the third and final prototype the quickest of the lot.
Having served its second purpose, the chassis was stripped and set aside late in 1954. It lingered in a corner for over 18 months before it was dusted off for its final transformation into the 150 GT. It was long believed and stated in the factory build sheets, that this car was actually based on a modified 150S / 200S chassis but more recent research by marque-expert Adolfo Orsi revealed the true origins of the heavily modified chassis. Using a competition chassis for the new road car made sense as the race shop was tasked with the development.
To accept a smaller four cylinder engine, the chassis was modified once more. The engine itself was derived from the 150S sports racer with the adoption of a wet sump being the only major change. It was mated to a conventional A6 GCS/53 gearbox, while the rest of the drivetrain included a 200S prop-shaft and A6 GCS/53 differential. The front suspension was virtually unchanged from its original configuration. At the rear a live axle with semi-elliptic leaf springs was used. The front brakes were borrowed from the 250F Grand Prix racer.
A product of Maserati's competition department, it is perhaps not surprising that the 150 GT was sent to Fantuzzi for coachwork and not to the likes of Frua, Zagato and Allemano, who traditionally bodied the company's road cars. This was Medardo Fantuzzi's first attempt at crafting a non racing body, and he was obviously inspired by the creations of the aforementioned. The result was a particularly attractive two-seater Spider body, which mixed the overall lines of Frua's finest work with a grill typically found on Zagato's designs.
Although the 150 GT Spider was a formidable machine, it was also far too complex and expensive to construct. The unique machine was nevertheless cherished and there were many within Maserati that hoped it would enter production after all once the 3500 GT had taken off. The prototype was, however, never shown at a major motor show but Maserati did lend it to important clients and even some journalists for road tests. Now stamped '03', the unique 150 GT Spider was finally sold to Maserati's London agent early in 1960.
The striking Maserati changed British hands several times, until it was acquired by a very private German collector in 1993. He eventually sold it to the current owner in 2006. Since then, it has been thoroughly researched and completely restored. At this time the engine was bored to two litres to make the car more drivable. Now fully sorted but still not shown at any major show, it will be offered by Gooding & Co. in their Scottsdale sale on January 19th. The pre-sale estimate for this one-off Maserati is a stunning $3 - 4 million.