Probably some of the most expensive Lamborghini models in existence today are these P538, in fact this is a car that wasn't built at the Lamborghini factory but by one of the people who were there in the very early days, Mr. Giotto Bizzarrini himself.
The latter designed the engine for the 350 GTV, and detuned it afterwards to fit the 350 GT needs of a quiet Gran Turismo. After that, Giotto Bizzarrini worked with Renzo Rivolta on his 'Iso', but later decided to build a race car, this became the P538.
The first prototype '001' of the 538 spider was built by Vincenzo Catarsi, who directed some boatyards in Vada. The final car would be sold to an American race driver Mike Gamino in late 1965, who ordered Bizzarrini to redesign the car a little and put a Lamborghini V-12 in the rear.
This engine was modified up to 4.0-Litre and developed 430 bhp at 8500 rpm, the six twin-choke Weber carburetors were retained and the car could reach a 170 mph top speed.
The fibreglass bodywork weighed only 40 Kg, while the weight of the entire car was only 700 Kg, with a length of 3990 mm and a height of 970 mm.
In the spring of 1966, the car was shipped to the United States were it was entered in several SCCA races, and it caused a lot of controversy on the track, according to sources it was extremely fast and handled like 'on rails'. Apparently it competed mostly in the Northeast region, were according to the legend surrounding it, it was banned in all local SCCA events.
This specific car was maintained at that time by Libero Girrardi, who kept it in his showroom after it's 'racing career' came to an end, subsequently it was sold to another enthusiast ... in the Eighties the car was again offered for sale, sitting in a local barn (I kid you not).
By then the car was in a very poor condition, the rather thin fibreglass bodywork was completely covered in cracks, the main frame rails that doubled as the transport for the coolant became totally rotten and the trans axle was missing. It still featured the Bizzarrini wheels but was now finished in a light blue color featuring a yellow stripe along the center of the car.
Also note that the engine now featured four triple choke Webers, a 24 plug setup and two massive Marelli 12 cylinder distributors, note that this very first Bizzarrini-Lamborghini P538 was valued between $1.500.000 and $2.000.000 when in perfect condition.
There have always been a lot of question marks around the Bizzarrini P538 cars, some were fitted with Chevrolet V8 engines, and at first it was believed that only one actually used a Lamborghini engine, but later a second one was located, chassis number 002 used a V12 from either the 400GT or the Islero as a power plant, I have received a photo with a small history and origin of this car ..., the facts are that now at least two of the original Bizzarrini P538 cars had a Lamborghini engine mounted ...
A Lamborghini fan was able to take photo's of this second P538 car, the owner stated that when Bizzarrini's factory closed down there was a second 'ghost' chassis in existence that was forgotten over the years. This second Lamborghini powered P538 was told to be finished by hand in 1967 by none other than Giotto himself, helped out by his wife Rosanna, this specific car was one of only two in existence and received a 420 Bhp V12 Lamborghini engine. This 002 car was built to be entered into the 24h of Le Mans in 1968, but it was excluded because engine size became limited to 3000cc for the Sports Cars, must have been nice to have seen just what the P538-002 could have done at Le Mans ...
In 1966 and 1968, two other cars were built on the same P538 chassis, but these were powered by Chevrolet V-8's, and were entered in European Grand Prix, while in 1981/82 two replica's were built by SD which were also equipped with a Chevrolet V-8 engine. These latter four may be less noble, but they are surely far easier to maintain than the Lamborghini V-12 powered ones.
In 1989 the very rare P538 was again shown to the public on the Pebble Beach Concours d'Elegance, were the freshly restored car was awarded a 3rd place in it's Class, for this show the rare Bizzarrini was cleaned up by Ultimate Motor Works in Florida who returned it to showroom condition by replacing the aged hydraulics, new electronics and some minor engine repairs, like an oil pump and some tuning of the impressive looking carburetors.
Also note the Ultimate Motor Works people went over the interior and exterior to make to car ready for judging during the concours, a little detail, in 1989 a Lamborghini powered P538 was appraised at US $ 1,800,000 and it was rumoured to be sold in 1990 for an estimated $ 1,500,000.
According to the latest information we were able to found on these rare cars, an original Lamborghini powered P538 ended up in the Netherlands at one point in history, this car was raced in Italy during the early Seventies, it was subsequently located in Switzerland at the Beuchi Restoration Shop for a certain amount of time.
One of the original P538 cars was later re-bodied as the Manta and ended up in a collection in Stockholm, another P538 was the Duca d'Aosta coupe, a closed version of the Bizzarrini car, this latter one is still located in the garage at the family home in Florence.
Later Diamante would build several P538 alike cars, he made several cars using parts Gioranengo bought from Bizzarrini, he was able to build a car for an enthusiast in Monaco, this car featured Alfa P33 wheels and today resides in the UK, several others are currently located in France, Belgium and Germany.
Very recently we also learned about the existence of a Bizzarrini Stradale 5300 with a Lamborghini V12 engine ... apparently the mystery surrounding these magnificent Bizzarrini cars will never cease to exist...