The Largest Mack Truck in the World is Back in Operation Following Extensive Restoration

      Anthony Lucibello via YouTube

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      The formidable M100SX is the largest bulldog ever manufactured by Mack Trucks. Only three units were produced in the 1960s, with only one still in existence today. A few years ago, it was obtained by The Mahan Collection Foundation in New Jersey, and I documented the story of the truck's revival after over fifty years. Now, the restoration is almost finished, and it’s operating under its own power once again, powered by its 1,788-cubic-inch diesel engine.

      If you’re interested in the complete history of the Mack—including the original build schematics and specifications—be sure to check out my detailed article from 2024. In case you're short on time, here’s a quick summary.

      Here’s a look at the truck when it was relatively new, around 1970. Via The Mahan Collection Foundation

      The vehicle you see here left the factory with a two-stroke Detroit 12V149T engine, producing 1,000 horsepower at 1,900 rpm. Initial measurements show it to be 32 feet and 1 inch long from the front bumper to the back of the frame, and it stands 13 feet and 6 inches tall. It weighed in at 95,485 pounds without the body, and its payload capacity exceeds 100 tons, supported by a GVWR of 331,875 pounds.

      After years of sporadic negotiations, The Mahan Collection Foundation finally acquired the M100SX. It had been sitting for an extended period at the Pile Foundation Construction lot in Far Rockaway, New York, on Long Island. Restoring it to working condition took nearly two and a half years, but the results speak for themselves:

      Mack M100SX rides again!

      You can hear the distinctive sounds of the big Detroit engine with its unique center exhaust stacks. Due to the size of the engine compartment compared to the cab—it’s vastly larger—the driver is positioned off to the right. And just to clarify, the truck is not designed to run wide open on highways; it has a top speed of only 28.8 miles per hour. The gearing is low, and movement is slow, which is typical for heavy off-road haulers like this one.

      I have contacted The Mahan Collection Foundation for more details about the restoration of the Mack. Hopefully, I will be able to provide you with a more comprehensive follow-up that outlines the extensive work involved. Regardless, we can all take joy in the fact that a part of trucking history is back on the road. It’s enough to bring a tear to one’s eye…

      Have a tip or question for the author? Reach out to them directly at caleb@thedrive.com.