Originally, the A20 Mack was used to plow snow and run equipment back and forth between locations.
"I worked at Mack for 25 years and used to work with this type of truck," Mason said. "I took a liking to it, so I bought it."
Despite the truck's age, Mason was able to drive the Mack from Hagerstown to his Sharpsburg-area home in 1983 without any problems.
"I don't know what I wanted to do with the truck originally. Just the fact that it was the first one impressed me," he said. "I just knew I wanted the truck, and I bought it off Mack for a very cheap price."
Mason and mechanic Ray Leman worked on the Mack, restoring the truck to its pristine 1950s state.
"I worked on the truck through the evenings, and on Saturdays and Sundays," Mason said. "Finding the parts, that's the big problem. There's only one place I can get parts."
He said the place to get parts is in the Adams County, Pa., area.
"I needed to replace a few things, and I wanted to use time-authentic parts," he said.
Some items that needed replacing included the brake lines, exhaust system, the headliner, the rocker panels, the wooden floor, heater core and radiator.
"I've put money into this truck, so I plan on keeping it up," Mason said.
With the A20 Mack completely restored, Mason shows off his truck proudly.
"A ... lot of labor and money went into this," he said. "My wife was leery about how much it was going to cost to restore it, but now that it's finished, she's so very proud of me."
Mason said he occasionally takes the truck out for a ride around town and sometimes his wife joins him.
"She said the seats are comfortable, but it rides a little rough," he said. "During the Sharpsburg parade, I had 28 adults and children riding. It was cramped."
At the parade, all 28 riders wore the same green T-shirts, which read: "Built like a Mack" and "First one built 1950 A20."
Mason said the truck has a practical side.
"It has probably been 15 years since this incident," he said. "A ... dump truck was moving a load in front of the schoolhouse one winter. The snow was pretty deep and the truck got stuck. When I passed by the first time, I tried to pull the (truck) out with my truck. The dump truck didn't budge. I left to get the Mack."
That, he said, did the trick. "That Mack has a lot of power behind it."
For information about the Mack Trucks Historical Museum, go to www.macktrucks.com and click on "Corporate." Then click on "Mack Museum."