Compare/International Harvester 1066 vs International Harvester 3688

International Harvester 1066 vs International Harvester 3688

Verdict: International Harvester 1066 vs International Harvester 3688

The International Harvester 1066 and the International Harvester 3688 are both tractors — here is how they stack up on the figures that matter. International Harvester 1066 leads on rated power with 116 hp against 114 hp. International Harvester 3688 is the lighter machine (11,300 kg vs 12,148 kg), which helps on soft ground and transport, while the heavier model carries more ballast for traction-limited draft work. International Harvester 3688 is the newer design (1981 vs 1971). In short: choose the International Harvester 1066 for outright pulling power, or the International Harvester 3688 if a tighter budget and lighter footprint matter more. Compare the full spec tables below before booking a demo.

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Acreage600 acBudgetMain crop / use

Fit & specs

International Harvester

Fit score

Best match

Clear

International Harvester

Fit score

Best match

Clear

Rated power

116 hp

114 hp

Confidence

40%

Guide price

—

Overview

Manufacturer

International HarvesterReference

Four gears (1-4) in two ranges (Low/High) with the two-speed Torque Amplifier power shift (TA/direct).Reference

With 18.4-34R1 rear tires.Reference

Total built

54,947Reference

2,572Reference

Final drives

—

bull gearReference

Differential lock

—

rearReference

Variants

1066 Hi-Clear

high-cropReference

—

3688 Hi-Clear

—

high-clearance modelReference

Engine

Fuel tank

159.0 LReference

—

Drawbar (claimed)

80.5 kWReference

74.7 kWReference

Drawbar (tested)

79.0 kWReference

74.0 kWReference

Displacement

6.8 LReference

7.1 LReference

Bore/Stroke

109 x 121 mmReference

109 x 127 mmReference

Air cleaner

dual stage dryReference

dual dry elmementReference

Rated RPM

2600 (after 1973)Reference

2400Reference

Starter volts

12Reference

Oil capacity

17.0 LReference

85.2 LReference

Coolant capacity

23.7 LReference

24.6 LReference

Power at rated engine speed

93.7 kWReference

84.8 kWReference

Max power

79.0 kWReference

74.0 kWReference

Compression

—

16:1Reference

Idle RPM

—

900-2400Reference

Transmission

Gears

infinite forward and reverse (two-range)Reference

16 forward and 8 reverseReference

Clutch

dry discReference

355.6mm cerametallic discReference

Transmission

Torque AmplifierReference

—

PTO & Hydraulics

PTO (claimed)

94.0 kWReference

84.3 kWReference

PTO (tested)

93.7 kWReference

84.8 kWReference

Type

hydrostaticReference

partial power shiftReference

Pump flow

45.4 lpmReference

68.1 lpmReference

Total flow

79.5 lpmReference

102.2 lpmReference

Steering flow

34.1 lpmReference

45.4 lpmReference

Rear Type

III/IIReference

IIReference

Rear lift (at 24"/610mm)

2540 kgReference

—

Rear PTO

independentReference

Rear PTO Type

540/1000Reference

540/1000 (1.375)Reference

Power at rated PTO speed

88.9 kWReference

83.9 kWReference

Hydraulic system

—

85.2 LReference

Capacity

—

85.2 LReference

Valves

—

2 to 4Reference

Control

—

draft sensingReference

Engine RPM

—

1000@2100Reference

Dimensions

Wheelbase

266 cmReference

Weight

12148 to 13345 poundsReference

11300 to 13200 poundsReference

Front tire

11L-15Reference

Rear tire

18.4-38Reference

18.4-34Reference

Ag front

11L-15Reference

Ag rear

18.4-38Reference

18.4-34Reference

Length

419 cmReference

467 cmReference

Width

248 cmReference

259 cmReference

Height (exhaust)

281 cmReference

—

Clearance (drawbar)

40 cmReference

—

Bar rear axle

82 mmReference

—

Operating

6053 kgReference

—

Ballasted

6921 kgReference

—

Height (cab)

—

284 cmReference

Shipping weight

—

5125 kgReference

Operating weight

—

5987 kgReference

Ground clearance

—

33 cmReference

Rear axle

—

82 by 2997 mmReference

Front tread

—

152 to 213 cmReference

Rear tread

—

167 to 326 cmReference

1066 Serial Number Location

1066 Serial Numbers

1971

7101Reference

—

1972

12677Reference

—

1973

24205Reference

—

1974

34949Reference

—

1975

46855Reference

—

1976

56672Reference

—

Test results

Fuel use

31.4 l/hourReference

26.9 l/hourReference

Max pull

5896 kgReference

5556 kgReference

Speeds

Capacities

Fuel

—

189.2 LReference

3688 Serial Numbers

1981

—

501Reference

1982

—

1743Reference

1983

—

2482Reference

1984

—

2695Reference

1985

—

3068Reference

Location:

—

Serial number plate on the right side of the tractor frame, ahead of the rear axle.Reference

Electrical

Ground

—

negativeReference

Battery volts

—

12Reference

Fit score weighs budget, operation size, crop match and data confidence against the details above. It’s guidance, not advice — always confirm with a dealer demo.