Chrysler LA 360 Specifications
| Engine Model: Chrysler LA 360 |
| Engine Type: 4-cycle 8-cylinder OHV 16-valve liquid-cooled gasoline |
| Total Displacement: 359.9 cu.in (5.89 L) |
| Rated Engine Power: 170-250 hp (126-185 kW) at 4400 rpm |
| Fuel System Type: Carburetor or electronic fuel injection |
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The Chrysler LA 360 (5.9L) is a legendary small-block
V8 engine introduced in 1971 as the largest and final displacement of the LA
(Lightweight A) family. Conceived during an era of tightening emissions
regulations and a shift toward more efficient powertrains, the 360 was
engineered for incredible durability and high torque output, securing its place
as a workhorse in trucks, vans, and select muscle cars.
Its production spanned over three decades, evolving from a carbureted,
low-compression design into the fuel-injected Magnum variant, which became a
cornerstone of Chrysler’s truck lineup through the early 2000s. The engine’s
robust architecture, featuring a cast-iron block and heads, made it a favorite
for high-mileage applications and performance builds, a legacy that continues in
the aftermarket today.
Engine Type: 90° V8, Gasoline, four-stroke.
Displacement: 5,898 cc (359.9 cu.in / 5.9 L).
Bore x Stroke: 101.6 mm x 90.9 mm (4.00 in x 3.58 in).
This bore dimension is the distinguishing feature from the LA 318, which shares
the same stroke but has a smaller bore.
Compression Ratio: The compression ratio varied significantly across the
engine’s lifespan. Early carbureted versions (1971-1980s) featured low
compression ratios ranging from 8.0:1 to 8.4:1 to accommodate the lower-octane
fuel and emissions equipment of the smog era. The later Magnum versions
(1993-2003) utilized a higher compression ratio of 9.1:1, made possible by
improved combustion chamber design and electronic fuel management.
Valvetrain: OHV (Overhead Valve / Pushrod), 16 valves (2 per cylinder). The
design utilizes hydraulic lifters, pushrods, and rocker arms to actuate the
valves, a configuration that contributes to the engine’s compact external
dimensions and low-end torque characteristics.
Power Output:
Carbureted (1970s-1980s): Output ranged from 170 to 245 hp @ 4,000 rpm, with the
higher figures reserved for 4-barrel carburetor applications in passenger cars.
Magnum (Fuel Injected, 1993-2003): Horsepower was rated between 230 and 250 hp @
4,400 rpm, with a focus on a broad, flat torque curve rather than peak
horsepower.
Torque:
Carbureted: Torque output ranged from 270 to 310 lb-ft, peaking at lower engine
speeds (around 2,400-3,000 rpm) to suit truck and heavy-duty applications.
Magnum: The fuel-injected Magnum engines produced 330 to 345 lb-ft of torque,
representing a substantial increase in low-end pulling power.
Firing Order: 1-8-4-3-6-5-7-2.
The cylinder block is constructed from cast iron,
providing a rigid foundation that contributes to the engine’s renowned
durability and noise, vibration, and harshness (NVH) dampening. It features a
deep-skirt design, where the block walls extend below the crankshaft centerline,
enhancing structural rigidity. The bore diameter is 101.6 mm (4.00 in).
Unlike the smaller LA 318, which is internally balanced, the LA 360 is
externally balanced. This is a critical distinction; the crankshaft, harmonic
balancer, and flywheel or flexplate are all specifically weighted for the 360’s
rotating assembly. The engine utilizes five main bearings, each with a two-bolt
main cap design, which is considered adequate for the engine’s intended torque
range and duty cycle.
The cylinder heads are constructed from cast iron,
sharing the same basic architecture as other LA-series small-blocks but with
larger intake and exhaust ports to accommodate the increased displacement. The
combustion chambers are of a polyspherical design in earlier versions, though
the later Magnum heads featured a more efficient fast-burn design with a
centralized spark plug location.
Valves are arranged in a wedge configuration. Intake valve diameter is 1.88 in
(47.8 mm) on standard 2-barrel engines, while performance and later Magnum
versions utilized a 1.92 in (48.8 mm) intake valve. Exhaust valves measure 1.60
in (40.6 mm). The valvetrain operates with stamped steel rocker arms (or later
Magnum pedestal-mounted rockers) and pushrods that transfer motion from the
hydraulic lifters located in the engine block.
The fuel system configuration is divided into two
distinct eras. The early LA 360 (1971-1991) was carbureted, utilizing either a
2-barrel carburetor for standard truck and economy applications or a 4-barrel
carburetor for performance and heavy-duty applications. The intake manifold was
a cast-iron unit. The later Magnum 5.9L (1992-2003) transitioned to a
multi-point electronic fuel injection (MPFI) system.
This system featured a high-flow composite or aluminum "beer barrel" intake
manifold, which significantly improved air-fuel mixture distribution and
atomization compared to the carbureted setup. The fuel injection system utilized
sequential firing of the injectors, controlled by a dedicated engine control
unit (ECU), which allowed for precise fuel delivery, improved cold starts, and
enhanced overall efficiency.
The lubrication system is a full-pressure, wet-sump
design. A gear-type oil pump, driven by the distributor shaft, draws oil from
the pan and circulates it through a full-flow oil filter before pressurizing the
main galleries. The system is designed to deliver a high volume of oil to the
heavy-duty reciprocating assembly, a necessity for an engine frequently used in
towing and high-load scenarios.
Oil pan capacity is 5.0 qt (4.7 L) including the filter. Recommended oil
viscosity is 10W-30 or 10W-40. A critical maintenance point for flat-tappet
versions (all pre-1993 models) is the requirement for oil with a high level of
ZDDP (zinc dialkyldithiophosphate) to protect the camshaft and lifters from
premature wear, a consequence of modern oils formulated for roller camshafts.
The cooling system is a liquid-cooled, pressurized
design utilizing a water pump mounted to the front of the engine block. Coolant
circulates through the cast-iron block and heads, with the flow directed to the
hottest areas around the exhaust valves and cylinder bores.
The system is designed for high heat rejection capacity to support the engine’s
use in heavy-duty trucks and vans. Total coolant capacity for the engine alone,
without the radiator and heater core, is approximately 5.0 qt (4.7 L). When
including a standard radiator and heater core, the total system capacity ranges
from 14.0 to 16.0 L (14.8 to 16.9 qt), depending on the vehicle platform.
Ignition System: Early LA 360 engines utilized a
breaker-point distributor, which was later replaced by an electronic ignition
system (Chrysler Electronic Ignition) in the mid-1970s. The Magnum engines
featured a distributor-less ignition system with a crankshaft position sensor
and coil pack, providing more precise spark timing and higher energy output.
Exhaust System: The engine uses a standard 4-into-1 exhaust manifold
configuration on each bank. The Magnum versions incorporated larger, more
free-flowing exhaust manifolds and a dual-outlet catalytic converter system to
optimize the performance of the fuel injection.
Balance System: The engine is externally balanced. The crankshaft, harmonic
balancer, and flywheel/flexplate are uniquely weighted for the 360. Using a
balancer or flywheel from an internally balanced engine, such as the LA 318,
will result in severe vibration and engine damage.
The LA 360 retains the compact dimensions of the LA
small-block family, allowing it to fit in engine bays designed for the smaller
273 and 318 V8s. The overall length, measured from the front of the water pump
to the rear of the flywheel, is 762 mm (30.0 in).
The width, measured across the valve covers, is 610 mm (24.0 in). The height
from the bottom of the oil pan to the top of the carburetor or intake plenum is
711 mm (28.0 in). The dry weight of a fully dressed engine (including intake
manifold, carburetor or fuel injection, water pump, and accessories) is 272 kg
(600 lb).
Valve Lash: Hydraulic lifters require no periodic
adjustment. However, pre-Magnum engines require pre-load adjustment during
assembly or rocker arm replacement.
Spark Plug Gap: For electronic ignition systems, the gap is 0.035 in (0.89 mm).
For the Magnum engines, the gap is specified at 0.040 in (1.02 mm) for the
platinum-tipped spark plugs.
Ignition Timing: Base timing for carbureted engines is typically 10° BTDC
(before top dead center) at idle with the vacuum advance disconnected. Magnum
engines utilize base timing controlled by the ECU and are not adjustable via a
distributor.
Idle Speed: Carbureted models typically idle at 600-700 rpm for manual
transmissions and 650-750 rpm for automatic transmissions in neutral. Magnum
engines have a controlled idle speed of 750-800 rpm.
Drive Belt Tension: Accessory drive belts (alternator, power steering, water
pump) require a deflection of 10-13 mm (0.38-0.50 in) under moderate thumb
pressure at the longest span between pulleys.
Cylinder Head Bolts: 70 lb-ft (95 Nm) for early LA
engines.
Cylinder Head Bolts: 50 lb-ft (68 Nm) for Magnum engines.
Connecting Rod Bolts: 45 lb-ft (61 Nm) for standard LA engines.
Main Bearing Caps: 85 lb-ft (115 Nm) for standard LA engines.
Intake Manifold (LA): 20 lb-ft (27 Nm).
Intake Manifold (Magnum): 40 lb-ft (54 Nm).
Rocker Arm Shaft (LA): 17 lb-ft (23 Nm) for the rocker shaft mounting bolts.
Rocker Arm Pedestal (Magnum): 21 lb-ft (28 Nm).
Oil Pan Bolts: 8-10 lb-ft (11-14 Nm).
Spark Plugs: 25 lb-ft (34 Nm) for tapered seat plugs.
Spark Plugs: 18 lb-ft (24 Nm) for gasket-type plugs.
Flexplate / Flywheel to Crankshaft: 55 lb-ft (75 Nm).
Water Pump: 30 lb-ft (41 Nm) for the water pump mounting bolts.
The LA 360 was utilized across a wide range of
Chrysler, Dodge, and Plymouth vehicles, as well as later Jeep models. Its
primary application was in trucks and vans, where its torque and durability were
most valued.
Dodge Ram (B-Series and Ram Pickup): 1971-2003. This was the engine’s
longest-running and most prolific application, serving as the premium
small-block V8 option. Dodge Challenger: 1971-1974. Offered as a
high-performance alternative to the 340 and 383. Dodge Charger: 1971-1974.
Featured in the final years of the classic Charger body style.
Plymouth Barracuda: 1971-1974. Available as a performance option in the final
generation of the E-body Barracuda. Plymouth Road Runner and Satellite:
1971-1974. Served as a potent V8 option in these intermediate models. Chrysler
Cordoba: 1975-1979. Became the standard and often only V8 engine for this
personal luxury coupe.
Dodge Van and Ram Van: 1971-2003. A staple in full-size vans for its high torque
and reliability. Jeep Grand Wagoneer: 1992-1993. The LA 360 (as a 5.9L) was the
final engine offered in this iconic luxury SUV before its discontinuation. Dodge
Durango: 1998-2003. The 5.9L Magnum was the top engine option in the
first-generation Durango.
Dodge Dakota R/T: 1998-2003. The Magnum 5.9L was exclusively offered in the
high-performance Dakota R/T, a sport truck package. Dodge Ramcharger and
Plymouth Trailduster: 1974-1993. Served as the premier V8 engine in these
full-size SUVs. Plymouth Fury and Dodge Monaco: 1971-1978. Featured in police
packages and as a high-performance option in full-size sedans.
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