• 300/340 Engine Specifications

    General Specifications for the 1966 Buick 300 and 340 Cubic Inch Engines The following information has been directly complied from original Buick service manuals for the respective year of vehicle manufacture. These specifications should also be correct for the 1967 model year.

            contributed by Aaron

    Bolt Torque Specifications
    AREA:Torque Lb. Ft.
    Spark Plugs25-35
    Crankshaft bearing caps to cylinder block95-120
    Connecting rods30-40
    Cylinder head to cylinder block65-80
    Harmonic balancer to crankshaft140 MINIMUM
    Fan driving pulley to harmonic balancer18-25
    Flywheel to crankshaft (both auto and manual)50-65
    Oil pan to cylinder block09-13
    Oil pan drain plug25-35
    Oil pump cover to timing chain cover08-12
    Oil pump pressure regulator retainer25-30
    Oil screen housing to cylinder block06-09
    Oil pan baffle to cylinder block09-13
    Oil galley plugs20-30
    Filter assembly to pump cover10-15
    Timing chain cover to block17-23
    Water pump cover to timing chain cover06-08
    Fan driven pulley17-23
    Thermostat housing to intake manifold17-23
    Intake manifold to cylinder head45-55
    Exhaust manifold to cylinder head10-15
    Carburetor to intake manifold10-15
    Fuel pump to cylinder block17-23
    Motor mount to cylinder block50-75
    Fuel pump eccentric to timing chain sprocket to camshaft40-55
    Rocker arm cover to cylinder head03-05
    Rocker arm shaft bracket to cylinder head25-35
    Delcotron (alternator) bracket to cylinder head 30-40
    Delcotron (alternator) bracket to water pump timing chain cover18-25
    Delcotron (alternator) mounting bracket thru Delcotron to cylinder head at pivot location30-40
    Starting motor to block30-40
    Starting motor brace to block09-13
    Starter motor brace to starting motor09-13
    Distributor hold down clamp10-15
    Manual lower flywheel housing plate (inspection cover)09-13
    Flywheel housing to cylinder block30-40
    Fuel filter to cylinder head10-15


     Wildcat 310
    (300 Cu, In.)
    Wildcat 350
    (340 Cu In.)
    Wildcat 375
    (340 Cu. In)
    Code number prefixMLMAMB
    Export code number prefixMMMCN/A
    Engine type90 V890 V890V8
    Bore and stroke3.750 x 3.4003.750 x 3.8503.750 x 3.850
    Piston Displacement300 Cu. In.340 Cu In.340 Cu. In.
    Carburetor type2 barrel2 barrel4 barrel
    Compression ratio9.0:19.0:110.25:1
    Gasoline requirementsregularregularpremium
    Brake horsepower @ RPM210/4600220/4000260/4000
    Maximum torque @ RPM310/2400340/2400365/2800
    Taxable horsepower33.74845.045.0
    Octane requirements motor858590
    Octane requirements research939399
    Cylinder numbers front to rear
    Left bank1-3-5-71-3-5-71-3-5-7
    Right bank2-4-6-82-4-6-82-4-6-8
    Firing Order1-8-4-3-6-5-7-21-8-4-3-6-5-7-21-8-4-3-6-5-7-2

    Piston and pin specifications:
    MaterialCast aluminum alloy
    TypeDivorced skirt
    FinishCam ground
    Piston Pins
    MaterialExtruded SAE-1018
    TypePressed in rod

    Crankshaft specifications:
    MaterialPearlitic malleable iron
    Bearings5 replaceable steel backed
    Bearing material#1, #2, #3, and #4 M/400 #5 M/100 Durex
    Bearing taking thrust load#3

    Camshaft specifications:
    MaterialCast alloy iron
    BearingsSteel backed Babbitt
    Number of bearings5
    Number of links54
    Crankshaft sprocketSintered Iron
    Camshaft sprocketNylon coated aluminum

    Lubrication system specifications:
    Type of lubrication
    Main bearingsPressure
    Connecting rodsPressure
    Piston pinsSplash
    Camshaft bearingsPressure
    Timing chainSplash and nozzle
    Cylinder wallsSplash and nozzle
    Oil pump typeGear driven
    Normal oil pressure33lbs. @ 2400 RPM
    Oil pressure sending unitElectrical
    Oil intakeStationary
    Oil filter systemFull flow
    Filter typeThrow away element and can
    Crankcase capacity
    Less filter4qts.
    With filter5qts.

    Piston Clearance limits
    Top land.0265-.0345
    Skirt- Top.0005-.0011
    Skirt- Bottom.0005-.0021
    Ring groove depth
    #1 compression ring.1855-.1930
    #2 compression ring.188-.1955
    #3 Oil ring.188-.1955
    Ring width
    #1 compression ring.0785-.0789
    #2 compression ring.0770-.0780
    #3 Oil ring.1810-.1870
    Ring gap
    #1 compression ring.010-.020
    #2 compression ring.010-.020
    #3 Oil ring.015-.035
    Piston pin length3.060
    Diameter of pin.9394-.9397
    In piston.0001-.0004
    In rod.0007-.0015 Press
    Direction and amount off set in piston.040 Toward high thrust side
    *All measurements are in inches unless otherwise specified

    Camshaft specifications:
    Bearing journal diameter
    Journal clearance in bearings.005-.0035 (#2, #3, #4, & #5)

    Connecting rod specifications:
    Bearing length.737
    Bearing clearance (Limits).0020-.0023
    End play- Total for both rods.006-.014

    Connecting rods:
    MaterialPearlitic malleable iron
    Rod bearingRemovable steel backed M/400

    Ring specifications:
    #1 compressionCast iron-chrome plated
    #2 compressionCast iron-lubrited
    Oil control Steel-uncoated
    Oil ring expanderSteel humped ring
    Ring locationsAbove pin

    Valve specifications:
    Intake valve materialSAE 1041 steel
    Exhaust valve materialGM-N82152 (21-4N)
    Valve lifter mechanismHydraulic
    Valve springSingle helical

    Cooling system specifications:
    System typePressure
    Radiator cap relief pressure15 PSI
    ThermostatChoke type opening at 180
    Water pump
    GPM @ RPM14 @ 100
    BearingsDouble row
    By-pass recirculation typeExternal

    Cooling system capacities:
     (300 Cu. In.)(340 Cu. In.)
    With heater12.7qts.12.7qts.
    W/O heater12.2qts.12.2qts.
    With air conditioning (all except 300 station wagon)14.0qts.14.7qts.
    With air conditioning (Station Wagon)14.7qts.14.7qts.

    Fan diameter and number of blades:
    Less AC18 x 4
    With AC18 x 7
    Fan Drive
    Less ACWater pump shaft
    With ACTorque and temperature sensitive clutch

    Valve system specifications:
    Rocker arm ratio1.6 to 1
    Rocker arm clearance on shaft.0017-.0032
    Valve lifter diameter.8422-.8427
    Valve lifter clearance in crankcase.0015-.003
    Valve lifter leak down rate12 to 60 sec. In test fixture
    Intake valve
    Head diameter1.8175-1.8075
    Seat angle45
    Stem diameter(top) .3415-.3412 (bottom) .3405
    Clearance in guide.0012-.0032 & .0003 max taper
    Valve spring
    Valve closed- Pounds @ length64 5 @ 1.727
    Valve open- Pounds @ length164 6 @ 1.340
    Exhaust Valve
    Head diameter1.380-1.370
    Seat angle 45
    Stem diameter(top) .3402-.3412 (bottom) .3397-.3407
    Clearance in guide(top) .0015-.0035 (bottom) .0021-.004
    Valve spring
    Valve closed- Pound @ length64 5 @ 1.727
    Valve open- Pound @ length164 6 @ 1.340

    Crankshaft specifications:
    Endplay at thrust bearing.004-.008
    Main bearing journal dia. 3002.4995
    Main bearing journal dia. 3402.9995
    Crankpin journal diameter2.0000
    Main bearing overall length
    Main bearing to journal clearance.0004-.0015

    Comments 2 Comments
    1. Buick2's Avatar
      Buick2 -
      These torque specs are really useful, but I find it hard to understand that there is no difference when dealing with the iron heads of the later 300s and 340s and the much sought after aluminum heads and intake manifolds of the '64 300ci engines. Should you really treat those the same?

      Hope someone can put my mind at ease since I have a '64 300 and a 67 340.

    1. BigDonno's Avatar
      BigDonno -
      Quote Originally Posted by Buick2 View Post
      These torque specs are really useful, but I find it hard to understand that there is no difference when dealing with the iron heads of the later 300s and 340s and the much sought after aluminum heads and intake manifolds of the '64 300ci engines. Should you really treat those the same?

      Hope someone can put my mind at ease since I have a '64 300 and a 67 340.

      The 1964 Buick manual for 4300 Skylark head bolt torque is 65 to 70 ft. lb. All 3/8 screws into the heads are limited torque from 10 to 15 ft. lb. Rocker stands, intake and exhaust manifolds. My heads, block and pan are painted gray aluminum metalic.