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A Rare Survivor from the Golden Age of American Trucking
The Mack B71 is a diesel-powered heavy-duty truck produced between 1953 and 1958, with only 522 units ever built. It stands apart from other B-series models due to its distinctive front-end design, extended radiator shroud, and factory-installed Cummins NHB 743 cu.in. turbocharged engine, rated at 200 horsepower. With a BBC (bumper-to-back-of-cab) length of 112.5 inches, the B71 was engineered for long-haul durability and mountainous terrain, often favored by West Coast operators.
Unlike its gas-powered siblings—such as the B42 and B61—the B71 was part of a diesel-only lineage that included the B73 and B75. These odd-numbered models typically featured Cummins engines, while even-numbered variants leaned toward Mack’s own inline sixes like the END673 and END711, which evolved from 211 to 250 hp over time with turbocharging and head gasket improvements.
Mechanical Features and Build Configuration
The B71 was equipped with:
Historical Context and Collector Sentiment
The B71 is not just a truck—it’s a time capsule. One unit, hidden in a quiet valley in Washington State, remains intact with 221,000 original miles, factory keys, and minimal rust. Its preservation is remarkable, considering most B-series trucks were either scrapped or heavily modified. Enthusiasts warn against altering such survivors, citing the “truck gods” who frown upon unnecessary modernization.
Collectors often seek original driving lights, visors, and trim pieces to restore authenticity. Some even sketch pen-and-ink renderings of their dream builds, imagining twin horns, 6-inch straight stacks, and white-painted steel wheels. But the consensus remains: keep it original, or risk losing the soul of the machine.
Transmission and Engine Pairings Across the B-Series
The B-series lineup included:
Restoration Advice and Parts Sourcing
For those restoring a B71:
Conclusion
The Mack B71 is a rare and revered piece of trucking history. With its Cummins heart, rugged drivetrain, and unmistakable silhouette, it represents a bygone era of American engineering. Whether tucked away in a wheat field or rolling down a parade route, the B71 commands respect—not just for its power, but for its story. Preserving these machines means preserving the legacy of the men and women who built, drove, and believed in them.
The Mack B71 is a diesel-powered heavy-duty truck produced between 1953 and 1958, with only 522 units ever built. It stands apart from other B-series models due to its distinctive front-end design, extended radiator shroud, and factory-installed Cummins NHB 743 cu.in. turbocharged engine, rated at 200 horsepower. With a BBC (bumper-to-back-of-cab) length of 112.5 inches, the B71 was engineered for long-haul durability and mountainous terrain, often favored by West Coast operators.
Unlike its gas-powered siblings—such as the B42 and B61—the B71 was part of a diesel-only lineage that included the B73 and B75. These odd-numbered models typically featured Cummins engines, while even-numbered variants leaned toward Mack’s own inline sixes like the END673 and END711, which evolved from 211 to 250 hp over time with turbocharging and head gasket improvements.
Mechanical Features and Build Configuration
The B71 was equipped with:
- Mack gearboxes, including a main and auxiliary transmission with a Z-pattern shift
- Camelback suspension, a hallmark of Mack’s rugged rear axle design
- Top-drop rear drives, enhancing ground clearance and load stability
- Westinghouse air brake system, standard for its era
- Budd wheels, which were less common in 1956 compared to Dayton spoke rims
Historical Context and Collector Sentiment
The B71 is not just a truck—it’s a time capsule. One unit, hidden in a quiet valley in Washington State, remains intact with 221,000 original miles, factory keys, and minimal rust. Its preservation is remarkable, considering most B-series trucks were either scrapped or heavily modified. Enthusiasts warn against altering such survivors, citing the “truck gods” who frown upon unnecessary modernization.
Collectors often seek original driving lights, visors, and trim pieces to restore authenticity. Some even sketch pen-and-ink renderings of their dream builds, imagining twin horns, 6-inch straight stacks, and white-painted steel wheels. But the consensus remains: keep it original, or risk losing the soul of the machine.
Transmission and Engine Pairings Across the B-Series
The B-series lineup included:
- B42: Gas-powered, often with flathead sixes like Hercules or Continental
- B61: Mack END673, turbocharged to 250 hp in later years
- B73/B75: Cummins-powered, similar to the B71 but with different frame lengths
- B81: Heavy-duty variant used in quarries and coal hauling
Restoration Advice and Parts Sourcing
For those restoring a B71:
- Use OEM or reproduction driving lights from specialty suppliers
- Maintain original suspension geometry to preserve ride quality
- Avoid cutting or welding the cab unless structurally necessary
- Document serial numbers and factory options for historical accuracy
Conclusion
The Mack B71 is a rare and revered piece of trucking history. With its Cummins heart, rugged drivetrain, and unmistakable silhouette, it represents a bygone era of American engineering. Whether tucked away in a wheat field or rolling down a parade route, the B71 commands respect—not just for its power, but for its story. Preserving these machines means preserving the legacy of the men and women who built, drove, and believed in them.
