The M3 GMC was 20.46 feet (6.24 m) long, 6.45 feet (1.97 m) wide, 8.17 feet (2.49 m) high (including the gun shield), and weighed 20,000 pounds (9.1 t).
It had a White 160AX 147 horsepower (110 kW), 386 cubic inch (6,330 cc),[REF] 6-cylinder engine with a compression ratio of 6.44:1.