Weight
See also: Engine Weights
Datsun 1200 weighs about 1640 pounds (745 kg) depending on year, options, and how much fuel is in the tank. The weight of the fuel is about 30kg, so can affect the measurement substantially.
Documentation
CURB WEIGHT ... 1613 pounds (733 kg) 1971 USA sedan
Weight Distribution (Front/Rear)....54/46
Consumer Reports 1971 September Road Test
Weight .................. 14cwt (711 kg) 1200 4-door Sedan
Datsun 1200SSS Road Test by MOTORMAN magazine November 1972
Curb Weight: 1609 lbs (731 kg) 1971 USA Coupe
Mechanix Illustrated "We Test America's Most Economical Car"
| 4-dr manual | 1532 lbs (696 kg) |
| 4-dr auto | 1609 lbs (731 kg) |
| 2-dr coupe | 1520 lbs (691 kg) |
| 5-dr wagon | 1609 lbs (731 kg) |
| Truck | 1499 lbs (681 kg) |
Source: Aussie brochures:
Japan published weights
(source: Datsun factory parts catalog C-231 page L1)
B110S 690 kg STD trim B110SR 665 STD 2-dr sedan B110 700 DX 4-dr B110R 685 DX 2-dr B110A 735 4-dr AUTO B110RA 720 2-dr AUTO B110G 705 GL B110GR 690 B110GA 740 B110GRA 725 VB110 735 Van VB110S 715 Van STD KB110 695 Coupe KB110G 700 Coupe GL KB110A 730 Coupe AUTO KB110GA 735 Coupe GL AUTO B110GTK 710 Coupe GX B110GK 705 GX Sedan
Curb weight 2-dr coupe: 1650 lbs (750 kg) Curb Weight 2-dr sedan: 1630 lbs (741 kg) Add 75 lbs for automatic transmission (34 kg) Source: Nissan USA statistics 
Measured
It all depends on how much fuel is in the tank at time of weighing, and if using stock components which are generally lighter than non-stock wheels, tires and suspension pieces. Plus options like carpet, transmission type, etc.
Ute
Ange had his ute weighed pre-conversion. It was 730kg.
Ute: 730kg/1606 lbs (one example measured)
Coupe
Kelmo weighed his stock 1973 USA coupe, with aftermarket wheels.
Front left: 463 Front right: 464 Rear left: 385 Rear right: 375 Total: 1687 pounds (767 kg) F/R weight distribution: 55/45
http://i297.photobucket.com/albums/mm219/ddgonzal/wiki/datsunweight6-2011.jpg
Sedan
ddgonzal measured his stock 1972 sedan with 1/4 tank fuel: 1640 pounds (745 kg)
Comparison
Lighter is better — just ask Colin Chapmanᴳ
Lighter weight = faster acceleration, better fuel economy and better roadholding
Heavier weight = slower acceleration but increased ride comfort
580 &up kg old Miniᵂ 670 kg Fiat 850 Spiderᵂ 696-735 kg Datsun 1200 680-910 kg GEO Metroᵂ/Suzuki Cultus 760 kg Porsche Speedsterᵂ 800-840 kg Volkswagen Beetleᵂ 1050-up kg new MINIᵂ
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