It took Giotto Bizzarrini around five years to unleash the P538. That's because he originally created Automobili Turismo e Sport with ex-Ferrari engineers, where he created the famous 250 "Breadvan." He then joined Iso Rivolta before establishing Bizzarrini S.p.A in 1964.
Bizzarrini designed a couple of road-legal cars before the P538, but it was the latter that combined all of Giotto's innovative ideas. Featuring disc brakes at all four corners, a fully independent suspension, and a fiberglass body mounted over a tubular steel chassis, the P538 was one of the most modern race cars by the time it broke cover in 1965. But it was also incredibly beautiful for a low-slung barchetta.
The American underpinnings made it even hotter and appealing to both racing enthusiasts and car collectors of the era. No longer having access to Ferrari engines, Giotto turned to American power for the P538, something it had already done while working with Iso Rivolta. The engine of choice? A small-block, 5.4-liter V8 from Chevrolet. Bizzarrini went with the most iconic small-block V8 of the era, the 5.4-liter that GM offered in the Corvette, with up to 375 horsepower.
Giotto also built a couple of cars fitted with Lamborghini V12 power. One was shipped to the U.S. with a 4.0-liter engine and was raced at Can-Am, while the second one was prepared for the 24 Hours of Le Mans with a 3.5-liter unit. That's the same V12 that powered the 350GT and the Miura back in the day and became the basis for every Lambo V12 until the 2000s (up to the Murcielago).
Bizzarrini built only a handful of P538s, with most records reporting five examples. At least one was disassembled by 1970 and rebuilt for an American client in 1974. Was the P538 a successful race car, as Giotto had dreamed? No. Financial problems prevented Giotto from developing the P538 to its full potential, while new FIA rules ousted the car from European endurance racing.
But the P538 was proof that Italy still had a fighting chance against the Ford GT40 after Ferrari failed to recapture its glory at Le Mans in 1966. The P538 has also soldiered on as a fine example of Italian beauty powered by American muscle.
And yes, the P538 is a rare collectible nowadays. RM Sotheby's is offering one for €475,000 (about $576,560). It's a late model that Bizzarrini rebuilt in the 1970s, and it packs the massive Chevy V8. It's not the most valuable version out there, but it's arguably the rarest car you can buy for a half-million bucks.
That's barely enough to buy a pair of Ferrari 250 GTO wheels, but unlike the latter, the P538 is a truly unique piece of automotive art of unparalleled scarcity. And you can argue all you want, but nothing beats a big V8 in a race car. Not even a Ferrari V12. Hear for yourself!