LA 318: Information Compilation

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Previously, I wanted to put my favorite engine, a 440, in my '69 318 Charger as I rebuild the car.  However, as I've watched gas prices soar in the spring and summer of 2008, I've decided I can live with a 318, having previously driven a 318 and a 440.  So, lately, I've been accumulating information on the 318, which is usually only briefly mentioned and then overshadowed by the 340 and 360.  I thought I would post my 318 info here.  Maybe it will be valuable to those beginning to learn about the 318, maybe others will find mistakes and correct them here (I've certainly found a few inconsistencies among sources), and maybe others will add new information.  I hope this is helpful.

Please note that I have not captured every detail, which I think would be a book in length.  But, hopefully from here, you can either find what you need or figure out where to find it.  Very little of what follows is in my words.

LA 318: Information Compilation

The 318 engine was introduced in 1957 and remained in continuous production by Chrysler until 2002.  During this time, the 318 was produced initially in the A-engine family, then the LA-engine family, and finally in the Magnum family.  This article briefly describes all 318's, but is intended as a compilation of information on the (pre-Magnum) LA 318.

Chrysler A Engine Family
The Chrysler A engine is a small-block V8 automobile engine. It was produced from 1956 until 1966 (or 1967 in Canada), when it was replaced by the improved wedge-head Chrysler LA engine and big-block Chrysler B engine. These two V8's look similar but have different cylinder heads (the A is polyspherical), blocks, and intake components.

Plymouth's Introduction of A Engines
Plymouth offered polyspherical versions of Dodge's FirePower Hemi (Chrysler's first V-8, introduced in 1950, long after Ford began using V-8's en masse with the Flathead in 1932).  The A-block was introduced mid-way through 1956.  All A-engines were produced exclusively by Plymouth from 1956 until 1958, when Chrysler extended production to its other brands.

A 277
The 277 was the first real A-block engine, sharing almost nothing but the basic concepts with the Dodge engines. It displaced 277 CID (Cubic Inches of Displacement), and was produced for 1956. Bore was 3.75" and stroke was 3.12".

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A 318
The 318 was the longest-lived Chrysler A engine, produced from 1957 through 1966 when it was replaced by the LA 318. For 1957 and 1958, Plymouth was the only maker of the A 318, but after 1958 it was shared with the other Chrysler brands. It was sized at 318 CID with the same 3.91" bore as the A 301, but with a longer 3.31" stroke.  The A 318 used either a two-barrel carburetor and was rated at 230 hp, or a four-barrel carburetor (1958-1962) and was rated at 260 hp.  In 1960, the 318 CID Red Ram V8 produced 230 gross hp at 4,440 rpm, and 340 lb-ft of torque at 2,400 rpm, fed by a two-barrel carburetor and using a 9:1 compression ratio.  The 1957 A 318 had 9.25:1 compression and the following firing order: 1-8-4-3-6-5-7-2.

Dual-Quad A 318
A special 1957 dual-quad version of the A 318 used two four-barrel carburetors to produce 290 hp (the same power rating as the 1970 340 6-pack) at 5,400 RPM and 325 ft. lbs. of torque at 4,000 RPM, making the dual-quad 318 the highest-output A engine ever. It was used in the 1957 Plymouth Fury. The best known example of a dual-quad A 318 is in John Carpenter's film entitled Christine from 1983 written by Stephen King, featuring a red and white 1958 Plymouth Fury (2-door hardtop) with a push-button TorqueFlite transmission and a curb weight of 3,510 lbs.  The standard rear gear on a 1958 Plymouth Fury was 3.73.  Was the dual-quad A 318 produced in 1958, or only in 1957?

Chrysler LA Engine
The Chrysler LA engine was introduced in 1964, specifically the LA 273.  The LA engine was an evolution of the small-block Plymouth polyspheric-head A engine. LA has been described as "Light A" on Wikipedia and as "Low A" in How To Hot Rod Small Block Mopar Engines.  The LA engine is lighter and has a shorter deck height (9.6") than the A engine.  Note that the deck height (distance from crankshaft center to top of block at the cylinder) is incorrectly listed as 9.94" in Taylor and Hofer's How To Rebuild Small-Block Mopar Engines.  LA engines are pushrod OHV (Over Head Valve) designs, and use a 90-degree V block, weighing approximately 160 lbs. The combustion chambers are wedge-shaped (the valves are in a row), rather than the polyspherical combustion chambers in the Plymouth A engine or the hemispherical chambers in the Chrysler Hemi engine. All LA engines are cast iron, except for the Viper V10 derivative, which is aluminum. LA engines have the same 4.46" bore spacing as the A engines.

LA engines are difficult to distinguish from A engines, except that the A engine polyspherical cylinder heads are noticeably larger than LA engine cylinder heads.  The LA engine's block is fractionally smaller than the A engine's block, and considerably lighter due to improved casting techniques.

The LA engines have larger main bearings than many other engines, especially other small-blocks.  This increases durability.  Obviously, larger bearings last much longer.  The LA engine crankshaft rod journals are larger than those of the small-block Chevy.

The LA engine family is divided into two basic groups.  The original group consists of the 273 and 318.  These two engines are virtually identical except for the bore sizes.  The other, newer group consists of the 340 and 360.  The two groups differ mainly by the left side motor mount.  Therefore a 318 can be bolted in place of a 273, or a 360 in place of a 340, but not a 360 in place of a 318 without changing the mount.

Another method of division for the LA engine is to consider the 273, 318, and 340 as one group, and the 360 as its own.  For example, the 273, 318, and 340 share the same oil pan, 3.31" stroke, and main bearing diameters.  Only the 340 T/A race block comes with 4-bolt mains, though the standard 340 race block comes with provisions for 4-bolt mains, but only two are machined.  Each of these 4 blocks uses 6.123" rods.

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LA 318
The LA 318 was a 318 CID (5.2 L) descendant of the A 318. Like the A 318, it has a larger bore at 3.91" as well as a stroke of 3.31", with a bore-to-stroke ratio of 0.8465. The LA 318 appeared in 1967 shortly after the LA 273 from 1964, and proved tremendously successful. The Magnum version of the LA 318 was available until 2002 when its production ceased. The LA 318 has been produced longer and in greater volume than any other LA engine.  It has earned a reputation for durability and economy.  It uses hydraulic lifters and a two barrel carburetor for most of its production, though four-barrel Carter Thermoquad and Rochester Quadrajet carburetors were used in police applications starting in 1978. The 318 received roller lifters and a fast-burn cylinder head in 1985, and throttle-body electronic fuel injection for truck applications starting in 1988.

Excluding the Magnum 318, the LA 318 was produced through 1991.  The remaining information under LA 318 below excludes the Magnum 5.2 L.  The LA 318 continued the LA 273's reputation for reliability and fuel economy.  The LA 318 was never intended as a performance engine.  In 1978 the four-barrel was introduced on the 318, though the emphasis was not on performance.  Nonetheless, the 1978+ four-barrel 318 would have been a performer in a lightweight Duster, according to How To Hot Rod Small Block Mopar Engines.

The LA 318 shares a lot with the A 318.  The LA 318 is essentially a larger LA 273 273, with the same stroke.  According to Allpar, the LA 273 used the A 318's crankshaft, bearings, bearing caps, vibration damper, and connecting rods, but noted that pistons, cylinder heads, and camshafts were different.

Hot Rod Magazine's article, "Junkyard Jewel: 400hp 318", states that the LA 318's bore-to-stroke ratio is better than the Chevy 350 small-block's, and this ratio is the true measure of breathing potential per unit of displacement, even if the factory bore of 3.91" is below the prized 4.00".  It is also asserted that the rod ratio is one that "the competition would die for."  Finally, the author, Steve Dulcich, boasted that like "all Mopar small-blocks, the valves are inclined at an advantageous 18-degree angle, the realm of older Chevy NASCAR race heads."  It is mentioned that Dulcich's particular LA 318 had plenty of life left in it at 200,000 miles, which is also a common story among Mopar enthusiasts.

For disadvantages of the LA 318, Hot Rod notes the initially low compression, difficulty in finding pistons and rings, small valves, poor cylinder head flow, restrictive exhaust manifolds, and "meager" camshaft specifications.  Nonetheless, 400 hp was achieved without expensive parts, such as Edelbrock cylinder heads.

Mopar Muscle Magazine published an article in September of 2004 entitled "318 Engine Build – A Parts Book 400HP 318", also by Steve Dulcich.  After achieving 400 hp with a simple rebuild and inexpensive parts (including an oversized 750 cfm carburetor...oversized for ordinary street use), Steve introduced a 100-shot of nitrous, and claimed 509 hp @ 6,000 RPM, however he also switched from pump gas to 100 octane fuel.

Popular Hot Rodding published an article entitled "Mopar 318 Engine – Cheap As Dirt", again by Steve Dulcich, in which he did 5 builds, achieving peaks of 400-415hp.  He observed that, although 318 CID is small displacement, some smaller engines of other manufacturers have been highly revered, such as the 302 Chevy or Boss Ford.  He cites an example that the LS1 engine has a smaller bore, and the LS1 is known for breathing, so the fact that the 318's bore is smaller than 4.00" does not limit its breathing.  Steve explains that the 318 is a natural as a high RPM powerplant, and that it can be built for a ridiculously low price compared to other V-8's.  He also mentions one of the general Mopar advantages of the larger 0.904" lifter diameter, which allows for faster camshaft lobe ramp-up speeds than other manufacturers of the day.  The final engine build was also over-carbureted with a 750 cfm Mighty Demon, considering the opening discussion of ordinary street drivability.

It is interesting to note that, although the 318 may be appropriate as a "high RPM" engine, a commonly accepted safe upper limit for piston acceleration (PA) is 100,000 feet per second per second, or f/s^2.  Here is the PA formula:

PA = RPM^2 x Stroke x (1 + (1 / (2 * Rod Ratio))) / 2189

With a little manipulation it can be demonstrated that a 318 with a factory stroke (3.31") and factory rod ratio (1.85) reaches 100,000 PA at about 7,215 RPM.  Do not push a 318 with a factory stroke and rod ratio to this RPM, because a connecting rod may be thrown.  In 2008, Eagle has a $500 set of connecting rods (ESP-6123C3D) listed on Summit Racing with an advertised maximum RPM of 7,500.

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LA 318 Power Ratings
Year   Carburetor   Compression   HP   Torque   Normal Oil Pressure
1967-1969   2-barrel   9.2:1   230@4,400   340@2,400   45-65
1970   2-barrel   8.8:1   230@4,400   320@2,000   45-65
1971   2-barrel   8.6:1   230@4,400   320@2,000   45-65
1972*   2-barrel   8.6:1   150@4,000   260@1,600   45-65
1973   2-barrel   8.6:1   150@3,600   265@2,000   45-65
1974   2-barrel   8.6:1   170@4,000   265@2,600   45-65
1975-1991      ?

* In 1972, power ratings changed from SAE gross to SAE net.  SAE gross horsepower was measured with the engine on a stand without accessories, air cleaner, mufflers, and possibly with headers instead of the exhaust manifolds.  SAE gross horsepower represented the maximum theoretical power, not the power of an installed engine in a street vehicle, and it was often manipulated by the advertising and marketing staff.  By 1972, SAE net horsepower ratings were the standard, representing horsepower at the flywheel in a street vehicle.  The LA 318 retained 65% of its horsepower and 81% of its torque when the ratings changed from SAE gross to SAE net.

LA 318 Blocks
From 1967-1975, there was the Casting Number (CN) 2536030.  From 1976-1979, there was CN 4006730.  From 1980-1983, there was CN 4104230.  I do not have information on blocks from 1984-1991.  Although the first casting of the LA 318 block, which is prior to 1976, may be over-bored up to 0.060", the LA 318 blocks produced after 1975 are thin-wall cast blocks, and should not be over-bored beyond 0.030".  These blocks should be sonic-tested for core-shift, and if present, then these blocks should not be over-bored beyond 0.020".  LA 318 blocks should not be decked or milled more than 0.060"-0.075", and less is better.  Factory deck height is 9.6".  Hydraulic tappet bores require 0.001"-0.0015" clearance.

LA 318 Camshafts
All LA 318 camshafts are hydraulic.  In 1967, there was Part Number (PN) 2668362 with a valve lift of 3.90"/3.90" (intake/exhaust) and advertised duration of 244/244 (intake/exhaust) degrees.  In 1968-1970, there was PN 2899144 with 3.73/.400 at 240/248.  In 1971-1979, there was PN 3512635 with .373/.400 at 240/248.  In 1980-1983, there was PN 4179768 with .373/.400 at 240/248.  In 1980-1986, there was PN 4179768 with.373/.400 and 240/248 for the 4-barrel.  In 1985-1986, there was PN 4323239 with .391/.391 at 240/240 for a roller.
         

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LA 318 Carburetors
I do not have information on all carburetors and fuel injection systems on LA 318 engines.  General recommendations for the size of a carburetor in cubic feet per minute (CFM) tend to be around 600 for economical street use, 650 for street/strip, and 750 for racing only (for example, the 1966 limited-production racing version of the 273 had a 700 CFM Holley).  Bolig used the 650 CFM Speed Demon for his street rebuild in Mopar Muscle.  Most factory carburetors were two-barrels, and the LA 318 got its first production four-barrel in 1978.

LA 318 Connecting Rods
All stock, forged LA 318 connecting rods are 6.123" in center-to-center length.  Although How To Hot Rod Small Block Mopar Engines asserts that all stock, forged LA 318 connecting rods can handle up to 8,000 RPM on occasion, the above argument concerning piston acceleration and modern forged Eagle connecting rod specifications indicate either approximately 7,100 or 7,500 RPM.  The stock rod ratio of an LA 318 is 1.85, which is better suited for high-RPM horsepower than low-end torque.  Factory LA 318 connecting rods weigh approximately 726 grams.  Rod side clearance should be 0.009"-0.017".  The best rod bearing clearance is between 0.002"-0.003".  Rod bolts are 3/8".  In 1967-1971, there was part number (PN) 2406785, forging number (FN) 1618699, and a floating pin.  In 1972-1973, there were PN 2899061 and 2899495, FN 2899062, 2899486, 3418645, and 3870404, and a floating pin.  In 1974-1975, there was PN 2899061, FN 2899063, and a pressed pin.  In 1976-1986, there was PN 3751015, FN 3418645 and 3751016, and a pressed pin.  I do not have information on connecting rods from 1987-1991.

LA 318 Crankshafts
All LA 318 crankshafts are 90-degree, have 2.5" diameter main journals, 2.125" rod journal diameters, and 5 main bearings.  Most LA 318 crankshafts should use 6 bolts to connect to the flywheel or flex plate.  The only confirmed forged crankshaft was in 1967, Part Number (PN) 2268119, but there are rumors of others.  Regarding LA engines, the cast crankshaft made its first appearance in the LA 318.  Nonetheless, these cast cranks are reputed to be very strong and suitable for most racing applications, including Super Stock and bracket racing.  Cast crankshafts are cheaper and lighter than forged crankshafts, and for LA 318's, they are not externally balanced.  It has been mentioned that all LA 318's are internally balanced.  The following are cast crankshafts: PN 2843699 from 1968-1971, PN 3698267 from 1972-1974, PN 3751831 from 1974-1986, and PN 4227880 from 1980-1986.  I do not have information on cast crankshafts from 1987-1991.

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LA 318 Cylinder Heads
There is a large list of LA 318 cylinder heads in How To Hot Rod Small Block Mopar Engines, covering 1967-1987.  The W-2 (P3870812) is a cylinder head that was introduced in 1976 for racing purposes, but never used in production; an Econo W-2 (P4120043) exists as well.  The best, and maybe only, aftermarket LA 318 cylinder head is the Edelbrock Performer.  The maximum that LA engine cylinder heads can be milled is 0.060".

LA 318 Exhaust
The exhaust manifolds are notoriously restrictive.  Switching to headers significantly adds power and noise, but reduces durability and drivability, especially in colder climates.  The LA 318 came almost exclusively with single exhaust.  Street header pipe diameter should be somewhere around 1.75", and should be used with an H-pipe exhaust, which reduces exhaust noise.  The "H" should be rearward of the transmission mount and forward of the front U-joint.  The collectors of the street headers should be 2 ½"-3" maximum.

LA 318 Firing Order
1-8-4-3-6-5-7-2

LA 318 Flex Plates
From 1967-1977, there was Part Numbers (PN) 2400885 and 2204768, for a 10.75" and 11.75" torque converter, respectively.  I do not have information on flex plates from 1978-1991.

LA 318 Flywheel
The flywheel from 1967-1986 was Part Number (PN) 2264597, with a 10.5" clutch size and neutral balance.  I do not have information on flywheels from 1987-1991.

LA 318 Ignition
The LA engine was the first to convert from a point-based distributor to an electronic ignition in 1971-1973 (sources vary).  In the mid-1970's, Chrysler introduced the "Lean Burn" system in both its LA and B engines.  This was the first of the computer-controlled ignitions.  Popular aftermarket ignitions have been Mallory and Accel, and these have been displaced largely by MSD.

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LA 318 Intake Manifolds
There is a large list of LA 318 intake manifolds in How To Hot Rod Small Block Mopar Engines, covering 1967-1986.

LA 318 Oil
A rebuilt engine should be broken in with 20W-50 mineral oil, such as Valvoline, and a camshaft additive should be used at first.  Once broken in, it may be argued that it is best to switch to 10W-30 synthetic, such as Royal Purple, as long as engine clearances aren't too high, which would cause the oil pressure to be too low.  A zinc-based additive should be added to preserve the camshaft, even though it is asserted in How To Rebuild Small-Block Mopar Engines that additives are unnecessary because modern oil has all necessary additives already.  Don't take that chance with your camshaft.  Numerous articles declare synthetic to be superior oil (less friction is better for the engine, producing more horsepower, etc.), but caution it should be changed at the same frequency as mineral oil.  For example, in the referenced Mopar Muscle magazine article, peak horsepower increased by 9 from 385 to 394 by switching from 20W-50 mineral oil to 10W-30 synthetic Royal Purple oil.

LA 318 Oil Pan
The factory oil pan holds 4-5 quarts, which is adequate for the street, but not large enough for racing.

LA 318 Oil Pressure
As a general rule of thumb, 10 PSI of oil pressure is required for each 1,000 RPM that the engine turns.  This means that 30 PSI is needed to go 3,000 RPM.  These numbers are based on a hot engine with the oil up to the operating temperature.  The LA engine does not need as much oil pressure as some other engines, so it can be slightly under these numbers and still be okay.

LA 318 Oil Pump
The oil pump is located in the oil pan, bolted to the block in the area of the #5 main.  It is popular to change to the high-volume oil pump for higher performance, but the stock relief spring should be changed as well.

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LA 318 Pistons
All LA 318 pistons are cast aluminum.  The stock piston pin diameter is 0.9842" with a length of 2.99"-3.00", weighing 154.6 grams.  In 1967, there was Part Number (PN) 2808405, weighing approximately 592 grams, and with a pin height of 1.75".  In 1968-1969, there was PN 3004509, 592 g., and 1.77".  In 1970-1972, there was PN 3420222, 592 g., and 1.74".  In 1973-1984, there was PN 3685751, 594 g., and 1.74".  In 1985-1986, there was PN 4342772, 594 g., and 1.76".  I do not have information on pistons from 1987-1991.  In 3 articles in different magazines, Steve Dulcich uses Keith Black KB167 hypereutectic pistons for performance 318 builds.  There is also a forged version in the same compression range: KB844.

LA 318 Pushrods
All LA 318 pushrods were 0.28" in diameter and hydraulic in style.  In 1967, there was Part Number (PN) 2532152, which was 7.5" in length.  In 1968-1974, there was PN 2899561 at 7.5".  In 1975-1977, there was PN 3780148 at 7.5".  In 1978-1986, there was PN 4095291 at 7.515".  In 1985-1986, there was PN 4323205 at 6.766", which was for a roller set-up.

LA 318 Rings
All LA 318 factory rings are 5/64", and moly rings of this size are most suitable for the street.  1/16" rings are more appropriate for performance engines, and seal well at both low and high engine speeds.

LA 318 Rocker Arms
All LA 318 rocker arms were of the stamped style (as opposed to adjustable).  In 1967, there was Part Number (PN) 2536145-6.  In 1968-1973, there was PN 3004716-7.  In 1974-1978, there was PN 3418424-5.  I do not have information on rocker arms from 1979-1991.

LA 318 Rocker Shafts
From 1967-1986, there was Part Number (PN) 2532149.  I do not have information on rocker shafts from 1987-1991.

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LA 318 Spark Plug Gap
The spark plug gap ranges between 0.035"-0.060".

LA 318 Valves, Exhaust
In 1967-1974, there was Part Number (PN) 2465339 at 1.5" diameter.  In 1975-1978, there was PN 3830705 at 1.5".  In 1979-1986, there was PN 4100387 at 1.5".  In 1978-1986, there was PN 4100632 for a 4-barrel, at 1.6".  I do not have information on exhaust valves from 1987-1991.

LA 318 Valves, Intake
In 1967-1986, there was Part Number (PN) 2465335 at 1.75" diameter.  In 1978-1986, there was PN 3683801 for a 4-barrel, at 1.88".  I do not have information on intake valves from 1987-1991.

LA 318 VIN
Each VIN from 1968 to 1980 had 13 digits.  The 5th digit indicates engine displacement.  This may be a "G", indicating a 318 two-barrel from 1967-1980, or "H", indicating a 318 four-barrel from 1978-1980.  I do not have information on the more recent 17-digit VIN's newer than 1980.

LA 318 Vibration Dampers (Harmonic Balancers)
Except for 1967, all LA 318 vibration dampers are cast, as opposed to forged.  In 1967, there was Part Number (PN) 2658459.  In 1968-1969, there was PN 2658458.  In 1970-1971, there was PN 2951673.  In 1972-1974, there was PN 3614369.  In 1975-1977, there was a "Lean Burn" PN 3830481.  In 1976-1977, there was PN 3614369.  In 1978, there was PN 3830481.  In 1979-1980, there was PN 4095633.  In 1981-1986, there was PN 4173443.  I do not have information on vibration dampers from 1987-1991.

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Performance Packages for the LA 318
The following packages (Stage I – VI) have been copied from How To Hot Rod Small Block Mopar Engines.

Stage I
Cylinder Heads: Stock
Valves: Stock 1.74" Intake and 1.50" Exhaust
Compression Ratio: 8.0:1 with unleaded gas
Exhaust System: Stock manifolds, dual exhaust
Carburetion: Big 2-barrel or small 4-barrel
Intake Manifold: Stock cast iron
Ignition: Stock electric
Camshaft: 0.400"-0.420" valve lift, 240-250 adv. duration, 18-24 degree overlap, hydraulic
Special Applications: None.  Too mild.
Estimated Bracket ¼-mile E.T.: 16 seconds

Stage II
Cylinder Heads: Stock
Valves: Stock
Compression Ratio: 8.5:1 with unleaded gas
Exhaust System: Stock manifolds, dual exhaust
Carburetion: Small 4-barrel
Intake Manifold: Stock cast iron
Ignition: Stock electric
Camshaft: 0.420"-0.435" valve lift, 255-260 adv. duration, 30-35 degree overlap, hydraulic
Estimated Bracket ¼-mile E.T.: 15 seconds

Stage III
Cylinder Heads: Stock
Valves: Stock 1.74" and 1.50" back-cut
Compression Ratio: 9.0:1
Exhaust System: 340 manifolds, dual exhaust
Carburetion: Carter TQ or Holley spread-bore
Intake Manifold: Stock 318-340-360, cast iron TQ
Ignition: High-performance electronic ignition with vac. advance
Camshaft: 0.435"-0.455" valve lift, 264-272 adv. duration, 40-50 degree overlap, hydraulic
Estimated Bracket ¼-mile E.T.: 14 seconds

Stage IV
Cylinder Heads: 360
Valves: 1.88" and 1.60" with bracket valve job
Compression Ratio: 9.5:1 with unleaded premium gas
Exhaust System: Street headers
Carburetion: Carter TQ or Holley spread-bore
Intake Manifold: Holley single-plane Dominator
Ignition: High-performance electronic with race coil
Camshaft: 0.470"-0.485" valve lift, 280-285 (285-292 with manual transmission) adv. duration, 60-70 degree overlap, hydraulic
Estimated Bracket ¼-mile E.T.: 13 seconds

Stage V
Cylinder Heads: Ported 360
Valves: 1.88" to 1.60" with bracket valve job
Compression Ratio: 9.5:1 with unleaded premium gas
Exhaust System: Race headers
Carburetion: 750 CFM Holley
Intake Manifold: Holley single-plane
Ignition: High-performance electronic with race coil
Camshaft: 0.500"-0.530" valve lift, 280-290 (290-300 with manual transmission) adv. duration, 55-70 degree overlap, mechanical
Estimated Bracket ¼-mile E.T.: 12 seconds

Stage VI
Cylinder Heads: W-2 Econo
Valves: 2.02" and 1.60"
Compression Ratio: 11:1 with race gas
Exhaust System: Race headers
Carburetion: 750 CFM Holley
Intake Manifold: Holley single-plane
Ignition: Race electronic
Camshaft: 0.575"-0.600" valve lift, 290-300 (300-315 with manual transmission) adv. duration
Estimated Bracket ¼-mile E.T.: 11 seconds

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Magnum Engine
The LA family was updated and branded as the Magnum V6 and V8 in 1992. While the Magnum 3.9 L, Magnum 5.2 L, and Magnum 5.9 L engines were significantly based on the 239, the LA 318, and the LA 360 — respectively — many of the parts do not directly interchange. Magnum cylinder heads use a different oiling system. The intake manifolds share dimensions, but will not interchange without modifications. Chrysler's engineers redesigned the oil seals on the crankshaft to improve anti-leak seal performance. The valve covers on the magnum have 10 bolts rather than the previous 5, for improved oil sealing.

All but the Viper and Ram V10 were replaced by the new PowerTech V6 and V8 and Hemi V8 in 2002.  Production of the LA series was long handled by the Mound Road Engine factory in Detroit, Michigan. With most versions canceled, that plant was closed in 2002.

Magnum 5.2 L
The Magnum 5.2 L, released in 1992, was an evolutionary development of the LA 318 with the same displacement. The Magnum development included multi-port fuel injection, new cylinder heads with a closed combustion chamber, a new higher-flow valve angle, increased valve lift (due to 1.6 rockers replacing 1.5), and new intake and exhaust manifolds. SAE net power was up to 230 hp and 300 ft. lbs. Production of the Magnum 5.2 L ended with the 2003 model year Dodge Ram Van. It was replaced by the new 4.7 L PowerTech V8.


References, Book and Magazine

Bolig, R. (2008). "A Purely Budgetary Build". Mopar Muscle Magazine. October.

Dulcich, S. (2004). "318 Engine Build – A Parts Book 400HP 318". Mopar Muscle Magazine. September.

Dulcich, S. (2005). "Junkyard Jewel: 400hp 318". Hot Rod Magazine.

Dulcich, S. (?). "Mopar 318 Engine: Cheap As Dirt". Popular Hot Rodding Magazine.

Shepard, L. (1989). How To Hot Rod Small Block Mopar Engines.

Taylor, D. & Hofer, L. (1982). How To Rebuild Small-Block Mopar Engines.


References, Internet

Allpar. "Mopar LA Series Engines".

Wikipedia. "Chrysler A Engine".

Wikipedia. "Chrysler FirePower Engine".

Wikipedia. "Chrysler LA Engine".

[Foreman72]

dude huge thanks 4 this...wicked helpful to people like me who want the most out of a 318...i'm looking to copy popular hot rodding's set up w/ a fel minor changes

i got so pumped when i read it...power to the small blocks   

there is good stuff on moparts about these mills aswell...but yeah thanks again...i'll be visiting this info again and again...keep posting what you find...it really helps people like me out...

[acelondon]

i thought i had a lot of 318 research done...

WOW

[Bandit4142]

Thank you for a very in depth write-up.   Extremely helpful.   

[Belgium R/T -68]

Great input. I have a 318 2bbl in my chally vert that I will stress untill it stops breathing. then I will put
a Hemi in it. Is upgrading to 4bbl by only changing intake and carb giving anything?

[elacruze]

 

Good stuff!

I'm gathering info/parts for my 318 sneak-attacker pickup.