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Chronology of the LA series Chrysler V8 engines

3.9 - 5.2 - 5.9 - 273 - 318 - 340 - 360 - 355

(Thanks to Stephen Havens)

Mid-1964: the first LA engine, the 273, was released as a lightweight, compact V8 for
the new Valiant. It needed notches in the side of the block to clear the power
steering pump. It had two-barrel carburetor, mechanical cam, forged crank, and 8.8:1
compression.

  • 1965 - optional high-output version 273 has a more aggressive cam and four-barrel with 10.5:1 pistons; these will remain through 1966.
  • 1966 - bolt angle on the intake changes; 1964 and 1965 heads and intake are unique.
  • 1967
    - Larger version, 318 cubic inches, released with hydraulic cam, forged crank, two-barrel carb, 9:1
    pistons; truck motors receive water heated intake with no exhaust
    crossover.
  • 1968 -
    • 273 gets hydraulic cam and loses forged crank
    • 4bbl 318 loses forged crank
    • no more water heated intake on trucks
    • 340 released with forged crank, 4bbl, hydraulic cam (in 1968,
      only the 4 speed cars got a more aggressive cam in the 340, automatic
      cars got a cam that the next year would become standard in high
      performance small block mills). New heads, larger ports and valves
      first year for the dual plain intake 4bbl only.
  • 1969 - last year for the 273
  • 1970 - 340 gets Six-Pak, revised pushrod holes on these J
    heads for more meat in the intake runners. Also, T/A blocks with
    thicker webs for the ability to install 4 bolt mains on 2 3 and 4.
  • 1971 - 360 released, 2bbl hydraulic cam, cast crank, J heads
  • 1972 -
    • 318 and 340 compression drops into the 8s
    • 340 gets smaller valved J heads (previously all 340 except the
      six pack got X heads; Six=Pak J heads were machined for larger valves)
  • 1973 - last year for 340, all 2bbl intakes become dual planes
    with EGR valves; before all intakes were single plane except 340 4bbl
    manifolds
  • 1974 - 360 gets 340 cam carb and intake and is dubbed the E58 police engine. In 1975, the 360 is rated at 230 hp @ 4400 rpm, 300 lb-ft @ 3,600 rpm.
  • 1977 - altitude-adjustable carburetors for Fury/Monaco and Aspen/Volare sold in high altitude locations; low-slip torque converter for TorqueFlite.
  • 1978 - 318 gets 360 heads, cam, intake, and carb; the E48 is born. The 318 gets a lighter carburetor with "solid fuel metering" and the 360 gets additional throttle return springs. Second Generation Lean Burn debuts on both. California cars get a four-barrel 318. TorqueFlite gets lockup torque converter.
  • 1979 - the 360 E58's compression is dropped to 8.0:1 (from 8.4) and horsepower drops to 195 @ 4,000, with torque at 280 @ 2,400 rpm. The engine ceased car production in late 1980; in 1979 it was in the Volare, Aspen, Cordoba, Newport, and New Yorker. Mopar Performance releases "X block" for racers, which can be installed at 340 cubic inches or bored out to the recommended 355 cid (or further).
  • 1983 - 318 police head released, larger than 360 combustion chamber, added water passages for cooling
  • 1985 - Federal 318s went to a roller cam and lifters (unless they had the four-barrel carburetor), reducing friction and increasing longevity; valve shrouding was used to increase the burn rate; and the compression ratio was hiked from 8.4:1 to 9.0:1. Truck engines did not get the roller tappets at this time, according to Chrysler's literature of the day.
  • 1986 - 318 receives high swirl heads
  • 1987 - 3.9 is developed from 360
  • 1988 - 318 get hydraulic roller cam; 3.9 and 318 get throttle-body fuel injection
  • 1989 - 360 gets hydraulic roller cam
  • 1990 - All LA engines get a new single-lip (using a spring) positive-construction valve stem seal; the 5.9 gets a new dual-lip rear crankshaft seal as well. Both seals are made of Viton®.
  • 1991 - New head gasket for all LA engines; the new graphite-base, non-asbestos material resisted leaks better.
  • 1992 - Magnum appears on 3.9 and 318 (5.2)
  • 1993 - Magnum 360 (5.9) appears
  • 1999 - 4.7 V-8, the LA family's replacement, appears on the
    Grand Cherokee, with slow phase-in planned for other models (including
    V-10 and possibly V-6 derivatives).
  • 2002 - The 318 is gone, leaving the 360 as a high-power option on pickups until the Hemi is available. A larger Viper V-10 replaces the original.
  • 2003 - Truck V-10 cancelled; Viper V-10 continues the LA design into 2004, and is used in the Ram SRT-10.
  • 2007 - A new Viper V-10 will be introduced, worked over by McLaren.
  • 2012 - The Viper V-10 is moderately upgraded
EngineYears (USA)*StrokeBore
Motor vehicle Vehicle Engine Auto part Automotive engine part
3.91988-20033.313.91
2731964-69 3.31 3.63
318 (5.2)1967-2002 3.313.91
3401968-73 3.31 4.04
3551975?-20013.464.05
360 (5.9)1971-2002* 3.58 4.00
488 V-101991 - 20023.884.00
505 V-102002 -3.964.03
* "They put the 360 in a few of the trucks in early 2003." - Rovell Rangel

All horsepower ratings before 1970 are gross measurements (without accessories and such). Ratings after 1971 are net measurements and are lower even for the identical engine.

The A engine was produced from 1955 through 1966. The LA, introduced in 1964, had the same basic design but was very heavily modified. The lightweight ("L" A) or thin-wall casting and heads saved around 50 pounds; the wedge-shaped combustion chamber was much smaller than the A engines' poly heads, greatly reducing the size and allowing the first LA engine (273 V8) to fit into the small Valiant. The LA's valves were simpler too, saving money and size. The 273 ended up being only fifty pounds heavier than the 225-cid slant six.

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