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Poly 318 Engine Parts List

I have compiled a thorough parts list for the A318 using brands I use and trust or for availability for items that have limited manufacturers. For interchange information, see the parts interchangeable page. For other brands, these part numbers should cross-reference. Many of these parts can be found at Summit Racing, JEGS, Speedway Motors, Rock Auto, Napa Auto Parts, and other retailer.

Bearings:

  • Cam: LA273/318/340/360
    • King CS512BB, King CS512HP, King CS527BB, Clevite SH1112S, Clevite SH8755S
  • Mains: LA273/318/340
    • King MB558SI, King MB558XP, Clevite MS1344A, Clevite MS540P
  • Rods: LA273/318/340/360
    • King CR805SI, King CR805XPN, Clevite CB1779A, Clevite CB481P

Distributor: All LAs and Magnum 318/360 (see my ignition technical article for more details on selecting and tuning the ignition system)

  • Recommended: Richard Ehrenberg’s USA-made “HiRev 7500” distributor, control unit, coil, and ballast resistor.
  • Cheap units, such as Pertronix and Proform, are built with inferior components and often have reliability and performance issues for optimum performance and reliability.
  • 2000 – 2013 Mopar Performance distributors with the miniaturized Accel GM HEI internals are prone to erratic timing.

Distributor Gear: LA273/318/340/360

  • Comp Cams 420
  • Howards Cams 94415
  • Crower 76010

Distributor Intermediate Shaft Bushing: Melling M-63030B

Flexplate and Flywheel: 1962 onward A/LA273/318/340

  • LA360 flexplates/flywheels can either be neutral balanced or weighted to balance the rotating assembly. It is safer to stay away from the LA360 units unless they are verified to be neutral balanced.

Freeze Plugs

Gaskets

  • Full Set: FelPro FS7734PT2
  • Full Set: Best Gasket RS579G
  • Cylinder Head: FelPro 7734PT
  • Exhaust Collector: FelPro 9045
  • Exhaust Manifold: FelPro MS9342B
  • Fuel Pump: FelPro 6579
  • Intake Manifold (fiber, superior type): Best Gasket 18019 
  • Intake Manifold (steel, can leak depending on surface trueness): FelPro MS9344SH
  • Oil Pan: FelPro OS6566C@ or 1806
  • Thermostat Housing: FelPro 35063
  • Timing Cover Set: FelPro TCS65631 or TCS45284
  • Valve Covers: FelPro VS11828R or VS11828C
  • Valve Cover Bolt Seals with Steel Retainer (modification): Beck/Arnley 039-6659 (2003 – 2006 Honda Element EX 2.4L, info courtesy Michael Lindsay)
    • Note: These steel retainers are larger than the early 277/318 retainers but may be of interest to some.
  • All other gaskets: LA273/318/340

Heater Bypass Hose: DAYCO 70476 for 3/4″ barbs

Lifters

  • Solid: Melling JB2084 or Sealed Power AT2084
  • Hydraulic: Melling JB879
    • Note: LA lifters will fit but are taller than A lifters and require shorter pushrods.

Oil Filter (canister)

  • Gasket: FelPro 70522
  • Filter: Wix 51076

Oil Filter (spin-on)

  • Adapter Plate to Block: FelPro 70522
  • Very Short Filter 3.79”: Wix 51085
  • Short Filter 4.338”: Wix 51068
  • Standard Filter 5.18” 1 qt.: Wix 51515
  • Long Filter 7” 2 qt: Wix 51773

Oil Pump

Pistons

  • Cast: Egge L2050
  • Forged: Auto Tec 1001831 (318) 1001832 (390 stroker)

Piston Rings: LA318 unless overboring to 4”, then LA340

  • Mahle 40069CP (Moly)
  • Mahle 50069CP (cast)
  • Mahle 41226 (chrome)

Pulley (Crank)

  • 1956 – 1992 A/LA
    • Note: 1970 – 1992 LA273/318/340 dampers/pulleys have a slightly different pulley bolt pattern, so using a 1970 – 1992 pulley on a pre-1970 damper or pre-1970 pulley on a later damper requires elongating pulley holes, which will not have a negative impact on anything.

Pulley (Water Pump)

  • 1956 – 1969 A/LA when using iron lefthand intake short pump.
  • 1970 – 1992 LA when using aluminum righthand intake long pump.

Pushrods

  • Solid Lifter: MPR55 or Sealed Power RP3030 (5/16” x 8.418”)
    • Note: These are OEM lengths, but rebuilt/modified engines may require custom lengths and should be measured.
  • Hydraulic Lifter: MPR153 (5/16” x 8.364”)
  • Note: These are OEM lengths, but worn equipment on non-adjustable rocker arms or modified engines may require custom lengths and should be measured.

Rocker Arm Adjuster Screws (positive lock): 3/8″-24 such as Crane 99802

Rocker Arm Shaft Expansion Plugs: Dorman 555-082 (45/64″) 

  • Note: The poly rocker arm shaft expansion plugs are larger than the LA shaft plugs, and the A-block plugs are not reproduced. I have researched and personally tried five different plugs, and the 555-082 is the closet fit with the inside diameter of the shaft being a hair smaller than the plug’s specified smallest diameter but not enough to cause distortion issues.

Spark Plug: 3/8” short-reach Autolite 85, Champion 63 (formerly J12Y), etc.

  • Warning: Do not install LA-type 3/4″ long-reach plugs, such as Autolite 65. They will contact the piston.
  • Note: There is a lot of misinformation about spark plugs with some people claiming A-block engines will only run well with one brand over the other, which is inaccurate. Any reputable brand spark plug will perform just fine with a healthy A/LA ignition system.

Starter Motor: see my article on available starter motors

Thermostat: (see my cooling system article for selection and discussion)

  • 180°: Stant 45358
  • 180° High-flow: Mr. Gasket 4363
  • 195°: Stant 45359
  • 195° High-flow: Mr. Gasket 4365
    • Note: High-flow thermostats should be paired with a high-flow water pump and larger radiator for optimal utilization.

Timing Set: LA273/318/340/360

  • Cloyes C3002K (OEM-type single non-roller)
  • Cloyes C3028X (double roller w/ cam advance adjustment)
  • Cloyes 93503X9 (billet double roller w/ cam advance adjustment)

Valve Guides: 

  • K-Line for 3/8″ stems
  • Iron Reverse Spiral Oiling for 11/32″ and 5/16″ stems
    • Note: While bronze guides can be used on intakes, the exhaust guide protrudes deep into the bowl to where iron guides are stronger with less deflection.

Valve Springs: LA, such as Comp Cams 901, 994, etc.

  • Always follow the cam requirement for seat and open pressures

Valve Spring Keepers: LA 7 or 10 degree.

Valve Spring Retainers: LA 7 or 10 degree, such as Howards 97118

Valve Stem Seals:

  • 3/8″ Stem Positive Seal: FelPro SS72730
  • 3/8″ Stem Umbrella: FelPro SS70014

Water Pump: 

  • Use 1957 – 1969 A/LA iron pump for factory left-side intake and short pump to match A-block pulleys (see Figure 1 below).
    • OEM Type: WP58180, TFW43030 
    • High-flow: FlowKooler 1701
      • Note: Should use a high-flow thermostat for optimal utilization.
  • Use 1970 onward aluminum pump for right-side intake but will need 1970 onward pulleys since the pump is longer than the pre-1970 (see Figure 2 below).
    • OEM Type: WP58181, TFW43026
    • High-flow model: Tuff Stuff 1465NA
      • Note: Should use a high-flow thermostat for optimal utilization.

Figures

Mopar LA and Poly A Pulleys
Figure 1: Pre-1970 A/LA Pulley (left) and Post-1969 LA Pulley (right) (photo J. Lotspeich)

late Mopar LA water pump
Figure 2: 1970 Onward Long Water Pump w/ Right Intake (photo J. Lotspeich)