1971 Plymouth Road Runner Engine Options and Specifications
In 1971 the Plymouth Road Runner could be ordered with four different high performance engine options.
For the 1971 Road Runner, the 383 high performance 4 barrel engine was the standard engine. Three engine options were available including the 340 4 barrel, 440 6 barrel and the 426 Hemi.
This article will include the 1971 Road Runner engine options and their specifications. This includes the engine code, cost, displacement, horsepower, torque, compression ratio, camshaft, lifter type, valve sizes, bore, stroke, air cleaner, exhaust, fuel and carburetion.
1971 Plymouth Road Runner Engine Options and Specifications
The 1971 Road Runner was available with the following four engines.
- 340 4-barrel (Optional)
- 383 4-barrel (Standard)
- 440 6-barrel (Optional)
- 426 Hemi (Optional)
In 1971 the 340 4 barrel engine was added to the Road Runner lineup for the first time. The 383 engine had a decrease in compression ratio and horsepower. The 440 Six Barrel had a slight decrease in horsepower and compression ratio. The 426 Hemi horsepower and compression remained the same.
1971 was the first year the manufacturers rated horsepower and torque with gross and net ratings.
1971 Road Runner with a 383 4-barrel
Let’s begin with the specifications for the standard engine, the 383 4 barrel engine. The engine code was E65.
Of the four engines available for the 1971 Road Runner, the 383 had the largest reduction in horsepower and compression ratio compared to the year before.
Horsepower decreased from 335 to 300 gross and the compression ratio decreased from 9.5:1 to 8.5:1.
Let’s take a close look at the specifications.
Specifications | 383 4-barrel |
Displacement | 383 |
Bore and Stroke | 4.25″ x 3.375″ |
Horsepower (Gross) Horsepower (Net) | 300 @ 4,800 RPM 250 @ 4,800 RPM |
Torque (Gross) Torque (Net) | 410 @ 3,400 RPM 325 @ 3,400 RPM |
Compression Ratio | 8.5:1 |
Camshaft | High lift, high performance |
Cam Duration/Overlap | 268°/284°/46° |
Cam Lift | .450″/.458″ |
Lifter Type | Hydraulic |
Valve Diameter, Intake | 2.08″ |
Valve Diameter, Exhaust | 1.74″ |
Carburetion | Single 4-bbl |
Air Cleaner | Dual Snorkel |
Exhaust System | Dual, low restriction |
Fuel Recommended | Regular |
1971 Road Runner With a 440 6-barrel
The 440 Six Barrel was available as an option for the 1971 Road Runner. The engine had a slight reduction in horsepower and compression compared to the previous year.
The engine code was E87 and cost an extra $262.15. Let’s take a look at the specifications.
Specifications | 440 Six Barrel |
Displacement | 440 |
Bore and Stroke | 4.32″ x 3.75″ |
Horsepower (Gross) Horsepower (Net) | 385 @ 4,700 RPM 330 @ 4,700 RPM |
Torque (Gross) Torque (Net) | 490 @ 3,200 RPM 410 @ 3,200 RPM |
Compression Ratio | 10.3:1 |
Camshaft | High lift, long duration, high overlap |
Cam Duration/Overlap | 268°/284°/46° |
Cam Lift | .450″/.458″ |
Lifter Type | Hydraulic |
Valve Diameter, Intake | 2.08″ |
Valve Diameter, Exhaust | 1.74″ |
Carburetion | Triple Holley 2-bbl |
Air Cleaner | Unsilenced |
Exhaust System | Dual |
Fuel Recommended | Premium |
1971 Road Runner With a 426 Hemi
The 426 Hemi was available as an option for the 1971 Road Runner. Of all the 1971 Road Runner engines available, it was the only one that didn’t see any reduction in horsepower or compression ratio.
The engine code was E74 and cost an extra $883.55. Let’s take a look at the specifications.
Specifications | 426 Hemi |
Displacement | 426 |
Bore and Stroke | 4.25″ x 3.75″ |
Horsepower (Gross) Horsepower (Net) | 425 @ 5,000 RPM 350 @ 5,000 RPM |
Torque (Gross) Torque (Net) | 490 @ 4,000 RPM 390 @ 4,000 RPM |
Compression Ratio | 10.25:1 |
Camshaft | High lift, long duration, high overlap |
Cam Duration/Overlap | 284°/284°/60° |
Cam Lift | .490″/.481″ |
Lifter Type | Hydraulic |
Valve Diameter, Intake | 2.25″ |
Valve Diameter, Exhaust | 1.94″ |
Carburetion | Dual Carter 4-bbl |
Air Cleaner | Unsilenced |
Exhaust System | Dual, low restriction |
Fuel Recommended | Premium |
1971 Plymouth Road Runner With a 340 4-barrel
The 340 4-barrel was available as an option for the 1971 Road Runner for the first time. The rated horsepower for the 340 engine remained the same but saw a slight decrease in compression from the previous year.
The engine code was E55 and cost an extra $45.90. Let’s take a look at the specifications.
Specifications | 340 4-barrel |
Displacement | 340 |
Bore and Stroke | 4.04″ x 3.31″ |
Horsepower (Gross) Horsepower (Net) | 275 @ 5,000 RPM 235 @ 5,000 RPM |
Torque (Gross) Torque (Net) | 340 @ 3,200 RPM 310 @ 3,200 RPM |
Compression Ratio | 10.3:1 |
Camshaft | High lift, high performance |
Cam Duration/Overlap | 268°/276°/44° |
Cam Lift | .429″/.444″ |
Lifter Type | Hydraulic |
Valve Diameter, Intake | 2.02″ |
Valve Diameter, Exhaust | 1.60″ |
Carburetion | Single 4-bbl |
Air Cleaner | Unsilenced |
Exhaust System | Dual, low restriction |
Fuel Recommended | Premium |
That’s the complete list of engines available for the 1971 Plymouth Road Runner. If you have any questions to ask me about the engine options or specifications for the 1971 Road Runner car model, send us an email found specifically on my contact page or comment below.
About 38 years ago I assembled my first Mopar engine, it was for a 1970 ‘Cuda. It’s at that time my hands on experience with Mopar cars and engines, including the 440, started. Although my research of the engines started years earlier.
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Article Resources
- 1971 Plymouth Service Manual
- Google Books: Chrysler Engines 1922-1998