Losing something makes you appreciate it all the more. That sums up some of what Isuzu Commercial Truck of America felt when General Motors shut down its medium-duty truck business back in 2009—leaving Isuzu without a gasoline engine for its line of cabover trucks.

“We had a significant [number] of customers who used gasoline engines in their trucks, so that was definitely a blow,” relates Brian Tabel, Isuzu’s retail marketing manager.

N-Series gasoline trucks had been assembled by GM at its plant in Janesville, WI, a facility that ceased operations in 2009. But in May 2011, Spartan Motors started production of Isuzu N-Series trucks equipped with a Vortec 6L small-block V8 gasoline engine at its factory in Charlotte, MI. That engine produces 297 hp. and 372 lbs.-ft. of torque.

Not only did the absence of a gasoline N-Series seem to make the hearts of medium-duty fleets grow fonder, Tabel says, but demand for that gasoline spec ramped up as well.

“One of our N-Series trucks equipped with a diesel costs about $8,000 more than one spec’d with a gasoline engine,” he explains. And that is before the higher price of diesel fuel as well as the cost of diesel exhaust fluid required for the selective catalytic reduction system are factored in.

Suddenly, Isuzu found that customers who’d traditionally bought only diesels were giving gasoline a try.

“Typically, low-mileage operations get the best return on a gasoline spec, where trucks are averaging 25,000 mi. a year,” Tabel says. “Now, however, with the price gap so large, fleets with medium-duty trucks averaging 30,000 to 35,000 mi. per year are benefitting from the switch to gasoline.”

It helps that Isuzu’s latest iteration of its gasoline-powered N-Series cabover comes mated to a 6-speed automatic transmission with double overdrive and lock-up torque converter, whereas previous N-Series gasoline models were only offered with 4-speed automatic without such additional features.