[3] The basic design of the LA engine would go unchanged through the development of the "Magnum" upgrade (1992–1993), and continue into the 2000s with changes to enhance power and efficiency.

In the mid-1960s, Chrysler decided to adapt the 318 cu in (5.2 L) small block V8 into a lightweight, high output engine equally suited for drag strip or street performance use.

This also included shot peened hammer-forged steel connecting rods and high compression cast aluminum pistons with full floating pins.

A 4-barrel carburetor was mated to a high-rise, dual plane intake manifold feeding high-flow cylinder heads that are still considered among the best of that era.

The engine was equipped with hydraulic lifters and two bolt main bearing caps, leading some to initially underestimate the 340's potential.

This race-oriented version of the already high-performance 340 featured an aluminum intake manifold mounting three Holley carburetors, a dual points ignition system, and a heavy duty short block with additional webbing to allow for aftermarket installed 4 bolt main bearing caps.

The combination of increasingly stringent emission controlss, lowered octane, rising gasoline prices, and insurance company crackdown on high-performance vehicles saw the relatively expensive 340 detuned in 1972 with the introduction of low compression (8.5:1) small valve heads, and by mid-year a cast nodular iron crankshaft and a variety of other emissions related changes.

In 1974, with the introduction of the code E58 4-barrel dual-exhaust version, at 245 hp (183 kW) SAE net, it became the most powerful LA engine with the end of 340 production.

Power started dropping from 1975 on as more emission controls were added resulting with the 1980 E58 engine only producing 185 hp (138 kW) SAE net.

The 1978–1979 Li'l Red Express truck used a special high-performance 360 4-barrel engine with factory production code EH1 that was rated at 225 SAE Net HP in production form [5] The EH1 was a modified version of the E58 360 police engine (E58) producing 225 hp (168 kW) net at 3800 rpm due in part, that as it was installed in a "truck", and not a car, it did not have to use catalytic converters (1978 only) which allowed for a free-flowing exhaust system.

Due to additional modifications, the prototype Li'l Red Express truck tested by various period magazines ran appreciably stronger than actual production examples.

[7] The last variation of the LA series to be introduced before the Magnum upgrade was the 1988–92 throttle-body fuel injected, roller cam engine.

A Holley/Chrysler-designed, single-point, twin-injector throttle body assembly was mounted atop a slightly redesigned cast iron intake manifold.

The valvetrain was upgraded to include hydraulic roller lifters; however, cam specifications remained essentially unchanged.

The 5.9 L V8 engines followed suit in 1989, but also received the overall improved "308" cylinder heads (casting number 4448308) that featured significantly higher flowing exhaust ports and a return to the original 1971 (non-fast burn) combustion chamber.

However, with other manufacturers already introducing the superior multi-point fuel injection system, Chrysler considered a more drastic upgrade program.

This family of gasoline-burning engines lasted for over a decade, were installed in vehicles sold across the globe, and were produced in the millions.

[10] The cylinder heads were another fundamental change of the Magnum engine, being designed to meet stricter requirements in both power and emissions by increasing efficiency.

[9] Cast iron exhaust manifolds, less restrictive than units found on previous engines, were bolted to the outboard side of each head.

[12] In addition, the valve covers were made of thicker steel than earlier parts, and were installed with a silicone gasket.

[9] The valvetrain was also updated, although it was still based on a single, center-block located camshaft pushing on hydraulic lifters and pushrods, one for each rocker arm.

Because the new pushrods also served to provide oil to the top of the cylinder head, the rockers were changed to the AMC-style, screw-mounted, bridged half-shaft type.

[12] In addition, the oil boss located at the end of the cylinder head on the LA engine was left undrilled, as it was no longer needed.

However, the boss itself was left in place, perhaps to cut down on casting and machining costs, and to allow the use of earlier LA heads.

During normal idle and cruising, it began "closed-loop" operation, during which the module acted based upon inputs from a variety of sensors.

For 1994, horsepower was reduced to 175 hp (130 kW), mostly because of the installation of smaller-volume exhaust manifolds; torque ratings remained the same.

[2] Although Chrysler had already introduced an aluminum block Lamborghini-influenced V10 in the 1991 Dodge Viper,[19] this engine's roots trace to the genesis of the 5.2 L Magnum V8 in 1988.

[8] Valve covers were die-cast magnesium (AZ91D alloy), rather than stamped steel; this lowered noise levels and made for better gasket sealing.

[citation needed] Applications: Chrysler has offered a line of crate engines based on the Magnum designed to bolt into older muscle cars and street rods with little modification.

Some of the changes to facilitate this were using a 1970–93 coolant pump so that older pulleys and brackets could be used, as well as an intake manifold that uses a carburetor instead of electronic fuel injection.