All of the info that I have read states that the 5. 9 cummins got heavier as the generations were added on... that is why there is the descrepincy of the weights of the 12v. the early was in the 975 range and in later years the weight increased.
here are specs for the furd 6. 4
390 cubic inches, 6. 4 liters
Configuration: V-8
Compression Ratio: 16. 7:1
Bore: 3. 86 inches
Stroke: 4. 13 inches
Injection: Direct injection, high pressure common rail injection system
Aspiration: Twin sequential turbochargers
Valvetrain: OHV, 4 valves per cylinder
Oil Capacity: 15 quarts
Weight: approx. 1,150 lbs
Horsepower (peak)*: 350 HP @ 3,000 RPM
Torque (peak)*: 650 lb-ft @ 2,000 RPM
ooh ooh ooh. . found this too...comparison of the 3 Furd "engines"
7. 3 L 6. 0 L 6. 4 L
Weight: 920 lbs 966 lbs 1,150 pounds
Horsepower:* 275 @ 2800 RPM 325 @ 3300 RPM 350 @ 2000 RPM
Torque (lb-ft):* 525 @ 1600 RPM 570 @ 2000 RPM 650 @ 3500 RPM