Karmann was initially receptive to the idea and plans were made to have the car on the market by December of 1958, but Volkswagen, who had hired Karmann to build the body work for the Karmann-Ghia, was none too happy with this plan. They threatened to cancel their contracts with Karmann if they took on the P1800 for fear it competed with their cars. This proved a major setback and nearly killed the car altogether.
Volvo shopped the car to several other German firms, but determined none of them could meet Volvo’s quality standards. Petterson was not ready to give up, so he secured financing to buy the parts from Volvo and build the car on his own. Meanwhile, Volvo would say nothing on the status of the car. This changed when a press release was made public and Volvo chose to work with Jensen Motors to build 10,000 cars.
The original engine was a B18 producing 100 horsepower. It was developed from the B36 V8 that was then in Volvo trucks, which helped cut production costs and produced a very strong engine.
The car became quite popular during its production run, eventually selling 47,492 units. It also holds the Guinness World Record for being the car with the all-time highest mileage. Irv Gordon has driven his P1800S over three million miles.