Poly 318 Torque Specifications

(applicable to 277, 301, 303, 313, 318, and 326)

I have collected these poly A-block torque specs from a number of factory service manuals and fastener data and added process notes from my experience and industry standards. These torque specifications work for all 1956 – 1966 A-blocks regardless of displacement. They assume a fastener grade 5 minimum.

Accessories Brackets:

  • 3/8” bolt/nut: 30 ft.
  • 5/16” bolt/nut: 25 lb.

Alternator/Generator Adjusting Bolt: 200 in.

  • Apply antiseize to this bolt to stop corrosion with the aluminum alternator housing.

Bellhousing Bolts: 50 ft.

  • Note: For automatics, ensure torque converter snout notches are fully aligned and engaged with the transmission pump tangs before tightening bellhousing bolts. Failure to do so can result in broken bellhousing ears and/or flexplate.

Camshaft Sprocket: 35 ft.

Camshaft Thrust Plate: 180 in. 

Carburetor Base to Intake: 60 – 80 in.

  • Note: Tighten evenly in an “X” pattern over three sequences until the gasket seats. Overtightening can warp the baseplate/air horn and cause vacuum/fuel leaks.

Clutch Housing: 30 ft.

Connecting Rod Nuts: 45 ft.

Crankshaft End Bolt: 135 ft.

Crankshaft Main Caps: 85 ft. 

  • Follow Figure 1 sequence. Tighten in three steps of 30 ft., 60 ft., 85 ft. 

Cylinder Head Bolts: 85 ft.

  • Follow Figure 2 sequence. Seal bolt threads with Rectorseal 23631 or equivalent since they go into coolant. Tighten in three steps of 30 ft., 60 ft., 85 ft.

Distributor Hold-down: 180 in.

Exhaust Flange Nut/Bolt (7/16″-20): 40 lb.

Exhaust Manifolds to Heads: 25 ft.

  • Follow Figure 3 sequence. Seal lower studs with Permatex 80003 or equivalent since some go into coolant. Tighten in three steps. Recheck after multiple heat cycles. See my technical article on installation.

Flexplate to Converter: 270 in.

Flexplate/Flywheel to Crank: 55 ft.

Fuel Pump: 30 ft.

Intake Manifold: 30 ft. 

Motor Mounts:

  • Block, 7/16-20, Grade 8: 40 ft.
  • Chassis: 90 ft. for 1/2″ single stud mounts; snug using a nylock nut for later captured mounts that use a 5/8″ through bolt.
  • See Figure 5 for proper motor mount positioning.

Oil Drain Plug: 25 ft.

Oil Pump Cover: 120 in.

Oil Pump Mounting Bolts: 35 ft.

Oil Pan: 180 in. unless gasket seats sooner.

  • Work evenly from center out similar to Figure 4. Tighten in three steps.

Pulleys (water pump and crank 5/16″ bolts): 200 in.

Rocker Arm Jam Nut (aftermarket): 25 ft.

Spark Plugs: 30 ft.

Starter Motor:

  • Stud nut and through-bolt: 25 ft.
  • Bolt or stud into aluminum: 216 in.

Timing Cover:

Thermostat Housing:

  • Iron Intake: 180 in.
  • Aluminum Intake: 144 in.

Transmission Inspection/Dust Cover: 100 in.

Valve Covers: 20 in. unless gasket seats sooner

Water Pump: 30 ft.

Dodge Plymouth Chrysler Mopar Poly 318 A-block crankshaft main tightening sequence
Figure 1: Poly A-block Main Cap Torque Sequence
Dodge Plymouth Chrysler Mopar Poly 318 A-block cylinder head tightening sequence
Figure 2: Poly A-block Cylinder Head Torque Sequence
Dodge Plymouth Chrysler Mopar Poly 318 A-block exhaust manifold header tightening sequence
Figure 3: Poly A-block Exhaust Manifold Torque Sequence
Dodge Plymouth Chrysler Mopar Poly 318 A-block intake manifold tightening sequence
Figure 4: Poly A-block Intake Torque Sequence
Dodge Plymouth Chrysler Mopar Poly 318 A-block motor mount position
Figure 5: Correct Poly A-block and LA Motor Mount Bracket Position