1972 Plymouth Duster 340 Engine Specifications
In 1972 the Plymouth Duster 340 came with only one engine.
For the 1972 Plymouth Duster 340, the 340 high performance 4 barrel engine was the standard engine. No other engine options were available.
This article will include the 1972 Plymouth Duster 340 engine and its 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.
1972 Plymouth Duster 340 Engine Specifications
The 1972 Plymouth Duster 340 was available with the following engine.
- 340 4-barrel (Standard)
All Engine Horsepower and Torque Ratings Change
Prior to 1971 an engine’s gross horsepower and torque were used for the factory power ratings. In 1971, the manufacturers reported both gross and net horsepower and torque. Starting in 1972 SAE gross horsepower was no longer used and the SAE net horsepower became the new rating.
Gross and net horsepower are both measured at the crank. The difference is the use of engine accessories, air cleaner and factory exhaust to calculate net horsepower which is not used for gross horsepower.
Therefore, in addition to horsepower robbing internal engine changes, the net rating lowered the power numbers for 1972.
1972 Plymouth Duster 340 With a 340 4-barrel
The 340 4-barrel was the only engine for the 1972 Plymouth Duster 340.
The rated horsepower was drastically reduced due to the change from gross to net horsepower ratings. In addition, the compression was lowered from the previous year.
The 1.88″ intake valves were smaller than the 2.02″ valves the year before.
As of April 11, 1972 a cast crankshaft replaced the forged crankshaft starting with 340 engine serial number HM340R-3911-8000. In addition, a different damper and a torque converter and/or flywheel with special balance was used.
The engine code was E55. Let’s take a look at the specifications.
| Specifications | 340 4-barrel |
| Displacement | 340 |
| Bore and Stroke | 4.04″ x 3.31″ |
| Horsepower | 240 @ 4.800 RPM |
| Torque | 290 @ 3,600 RPM |
| Compression Ratio | 8.5:1 |
| Camshaft | High lift, high performance |
| Cam Duration/Overlap | 268°/276°/44° |
| Cam Lift | .429″/.444″ |
| Lifter Type | Hydraulic |
| Valve Diameter, Intake | 1.88″ |
| Valve Diameter, Exhaust | 1.60″ |
| Carburetion | Single Carter 4-bbl |
| Air Cleaner | Unsilenced |
| Exhaust System | Dual, low restriction |
| Fuel Recommended | Regular |
That’s the complete list of engines available for the 1972 Plymouth Duster 340. If you have any questions to ask me about the engine options or specifications for the 1972 Duster 340 car model, send us an email found specifically on my contact page or comment below.
About 39 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
- 1972 Plymouth Service Manual
- Google Books: Chrysler Engines 1922-1998
