Schwan’s Ford E-450s are among the many that run on propane, which the company has used since the 1970s. After more than 40 years of using propane as a motor fuel, the people at The Schwan Food Co.

FARGO, N.D. -- Bill Ongstad says converting his new 2013 Ford 350 to a propane bi-fuel system might save him 40 percent in fuel costs. "I figure to have it paid for by Christmas," says Ongstad, who ...