7 material differences · fewer than 12

Tractor oneInternational Harvester 6661972–1976No measured PTO figureTractor twoInternational Harvester 7061963–1967No measured PTO figure

Which should you choose?

We will not advise between these two machines, because the drive differs (2WD; Two-wheel or four-wheel drive); they were not built in overlapping years (1972–1976; 1963–1967). The figures below are side by side so you can judge them yourself; each says whether it was measured, claimed or declared by its source.

Field by field

7 material differences · 5 fields identical or within 5%, which is not counted as material

International Harvester 666 and International Harvester 706, field by field
Field	666	706	Gap
Engine
Engine power, claimed claimed	66.1 hp	66.1 hp	—
Engine declared	INTERNATIONAL HARVESTER C-291	INTERNATIONAL HARVESTER C-263 or C-291	differs
Transmission
Top speed declared	18.6 mph · 30 km/h	18.6 mph · 30 km/h	—
Clutch declared	Pedal-operated dry single-plate clutch	—	—
Hydraulics & hitch
Pump flow declared	12.0 gpm · 45.5 L/min	—	—
Rear PTO speeds declared	540 rpm	540/1000 rpm	differs
Weight & dimensions
Unladen weight declared	8,199 lb · 3,719 kg	8,285 lb · 3,758 kg	—
Wheelbase declared	103.0 in · 2,616 mm	87.0 in · 2,210 mm	+18% 666
Length declared	161.0 in · 4,089 mm	157.0 in · 3,988 mm	—
Width declared	87.0 in · 2,210 mm	92.0–110.0 in · 2,337–2,794 mm	differs
Height, over the steering wheel declared	77.0 in · 1,956 mm	80.0 in · 2,032 mm	—
Ground clearance declared	21.0 in · 533 mm	17.0 in · 432 mm	+23% 666
Turning radius, braked declared	12.0 ft · 3.66 m	10.7 ft · 3.25 m	+13% 666
Fuel tank declared	123.9 qt · 117.3 L	132.1 qt · 125.0 L	+7% 706

International Harvester 666 sources

Source

Source: Traktorenlexikon, “IHC 666”
Source: Traktorenlexikon, “Farmall Farmall 756”
Source: Traktorenlexikon, “Farmall Farmall 666”

International Harvester 706 sources