WASHINGTON (MarketWatch) -- The U.S. military’s humvee truck replacement is expected to cost the U.S. around $350,000 each, on average, before tacking on armor and any additional high-tech equipment, according to a Government Accountability Office report released this week.

Adding the armor would raise costs by an additional $60,000, while additional options could take the final price tag for some variants to $600,000, the investigative arm of Congress concluded.

The humvee — the Pentagon’s acronym for “high mobility multipurpose wheeled vehicle” — has been in production since 1985.

The Joint Light Tactical Vehicle is expected to have three variants, divided by weight class. The smallest class would be a general purpose utility vehicle; a mid-sized vehicle would carry troops and act as a mobile command center; the largest class could be used as a cargo carrier or an ambulance.

The Army disputed the numbers, saying the JLTV should cost between $230,000 to $270,000 each, depending on the variant, though that also excludes armor and additional mission equipment.

But the military’s numbers likely are wrong, said Winslow Wheeler, a former national security adviser to Congress and now director of the Strauss Military Reform Project, a think tank.