In the early 1970s, the great mystery supercar was the Monteverdi Hai. A 7.0-liter Chrysler Hemi was tucked in back of very exotic bodywork, apparently by Carrozzeria Fissore. Meant to take on Ferrari and Lamborghini, the Hai brought everyone’s attention to Peter Monteverdi. Sadly only two copies of the Hai were made at the time, but the result was everyone knew Monteverdi’s name.

The Swiss, an auto importer, had proved serious about producing cars in 1967 when the Monteverdi High Speed 375S coupe debuted at that year’s Frankfurt Motor Show. Over the next 16 years, he would produce a series of vehicles, the most memorable being the Fissore-penned High Speed 375 series. Exotic cars built on several chassis lengths, they were also Chrysler Hemi-powered and done as two-door coupes, spyders and 2+2s. Also on the model list was a much larger version, a four-door sedan labeled the 375/4 with the wheelbase stretched 20.3 inches.

The same rather rectangular exterior design that graced the front and back of the coupes was used for 209.1-inch-long sedans. Back seat legroom was generous, the rear bolstered seats luxurious with the option of a 6-inch Sony TV set tucked in the rear of the center console. The 375/4s rode on a 125.2-inch wheelbase, and some specs put the weight at 4200 pounds. At the front are upper and lower A-arm suspensions while at the back is a De Dion layout with trailing arms. Disk brakes all around. Backing the Chrysler Hemi V-8 is a TorqueFlite 3-speed automatic. Claimed 0-60 mph is 7.5 seconds with a top speed of 146 mph.

Monteverdi apparently wasn’t the best at keeping production records, but most estimates are that fewer than 30 375/4s were created. It seems many were sold to Middle Eastern countries, and one report has the royal family of Qatar once owning five of the big Monteverdi sedans.