The 6C 1750 Gran Turismo Compressore Series V—GTC for short—represents the penultimate evolution of the 6C 1750. Produced from 1931 to 1932, the elegant, supercharged grand tourer was born of an effort to reinvigorate the 6C model line in the wake of the newly released and impressively sporty 8C 2300. It combined a detuned version of the more powerful 6C Gran Sport’s 1,752-cubic-centimeter supercharged engine—making a claimed 80 horsepower—with a streamlined, long-wheelbase chassis suited to refined saloon bodies. The GTC’s improved running gear included semi-elliptic springs, adjustable shock absorbers, larger brakes, and axles and a gearbox derived from the 8C. With the higher spec came a higher price. Well-heeled customers carefully chose bodies for the chassis from top coachbuilders, including Castagna, Touring, Zagato, and others. Though not on the level of a true sports racer, the GTC was nevertheless eminently competent: Two specially constructed, lightweight competition variants competed in the 1932 Mille Miglia, with one coming in fourth overall and winning the closed-car production class.

The example offered here appears to be the third-to-last of only 66 GTCs produced in 1931, based on its chassis number, and is believed to be one of only a few ever fitted with the sleek Coupé Royal body by Carrozzeria Touring. The two-door, four-seat coachwork showcased nascent aerodynamic principles, evident in the streamlined fenders, unusually domed roof, and sloping trunk, designed not for luggage but to store spare wheels without creating turbulence. Touring is said to have wistfully nicknamed its Coupé Royal body style “Fugientem Incurro Diem”—roughly translated from Latin to mean “And the time flies.”

This GTC’s history remains elusive prior to 1983, when Ugo Isgró of Silea, Treviso, Italy, acquired it from a gentleman from Turin. Isgró consulted with well-known coachwork restorer Dino Cognolato at Carrozzeria Nova Rinascente in Vigonza, Padua, to have the body restored. Photos taken at that time show the car in extremely poor condition, even lacking an engine. Upon close inspection, telltale signs emerged—the single spear of chrome trim on each door (at least one other known GTC Coupé Royal had three trim spears) and the running boards and front fenders showing signs of previous modification—which pointed toward chassis number 101014859 possibly being the two-tone GTC pictured in period photos of the 1931 Concorso d’Eleganza Villa d’Este. Said to have been built for an Italian Marquis named Annibale Prosperini, the car, with its svelte silhouette and novel, curved running boards overlapping the front fenders, captivated attendees, ultimately winning its class.

Carrozzeria Nova Rinascente recommissioned the bodywork, to include expertly reconstructing the sloping rear trunk and restoring the overlapping running boards and front fenders to correct specification. Following completion of the work in 1984, now beautifully finished in the striking yellow and black livery it wears to this day, Isgró sold the car in 1985 to well-known Alfa Romeo collector Umberto Genovese. He, in turn, commissioned highly regarded Bonfanti Garage in Bassano del Grappa, Vicenza, to restore all the mechanicals to full factory specification. Shop owner and master restorer Gigi Bonfanti—hallowed in the halls of Alfa Romeo for his deep technical knowledge and enduring passion for the marque—would oversee all mechanical work, including sourcing and installing a correct, supercharged, 1,752-cubic-centimeter inline, six-cylinder engine. Fully restored at last, both cosmetically and mechanically, the GTC remained in Genovese’s collection for the next 30 years, continually serviced and maintained by Bonfanti Garage.

Acquired in 2015 by the current owner, this cherished GTC continues to be lovingly maintained and sparingly driven. Prior to being imported to the United States in late 2016, Bonfanti Garage recommissioned various components, including the clutch and radiator. Accompanying the sale are copies of previous Italian registration documents, photos of the 1980s restoration, and service invoices for work completed under current ownership.

Though no documents survive to definitively confirm that this car belonged to Marquis Prosperini, intensive research by marque experts points toward that conclusion. Regardless, as possibly the only surviving 1931 6C 1750 GTC Coupé Royal restored to factory specification, it represents a truly rare opportunity for the discerning Alfa Romeo enthusiast.