In the 1950s, Dee Howard of San Antonio converted and rebuilt Lockheed B-34/PV-1 Venturas as executive transports, calling them the Howard Aero 250 and 350. Over a four-year period the company also built 16 new Model 350s, virtually by hand, which it called the Howard 500. The Howard 500 retains the general lines of the Model 350 and its powerplant, the 2,500-hp Pratt & Whitney R-2800 CB-16/17 radial engine. Six Model 500s exist today and only one is still flying. That airplane, a 1960 model and the fifth Howard 500 built, was displayed at Oshkosh by its owner, Phillippi Equipment of Eagan, Minn., which still flies it regularly. According to the company, the airplane cost $585,000 when sold in 1961.