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Buick 350 Engine Specifications and Blueprinting.


General Specifications for the 1970 Buick 35 Cubic Inch Engines. The following information has been directly complied from original 1970 Buick service manual.

Use a reliable torque wrench to obtain the figures listed below. This will prevent straining or distorting the parts as well as preventing thread damage. These specifications are for clean and lightly lubricated threads only. Dry or dirty threads produce friction which prevents accurate measurements of the actual torque. It is important that these specifications be strictly observed. Over tightening can damage threads. This will prevent attainment of the proper torque and will require replacement of the damaged part.

Bolt Torque Specifications
AREA: Torque Lb. Ft.
Spark Plugs 15
Crankshaft bearing caps to cylinder block 95
Connecting rods 35
Cylinder head to cylinder block 75
Harmonic balancer to crankshaft 120 MINIMUM
Fan driving pulley to harmonic balancer 23
Flywheel to crankshaft (both auto and manual) 60
Oil pan to cylinder block 14
Oil pan drain plug 30
Oil pump cover to timing chain cover 10
Oil pump pressure regulator retainer 35
Oil screen housing to cylinder block 8
Oil pan baffle to cylinder block 11
Oil galley plugs 25
Oil pressure switch to cylinder block 23
Filter assembly to pump cover 13
Timing chain cover to block 29
Water pump cover to timing chain cover 7
Fan driven pulley 20
Thermostat housing to intake manifold 20
Automatic choke cover to cylinder head 8
Intake manifold to cylinder head 55
Exhaust manifold to cylinder head 18
Carburetor to intake manifold 13
Fuel pump to cylinder block 20
Motor mount to cylinder block 63
Fuel pump eccentric to timing chain sprocket to camshaft 48
Rocker arm cover to cylinder head 4
Rocker arm shaft bracket to cylinder head 25
Delcotron bracket to cylinder head 35
Delcotron adjusting bracket to cylinder head 22
Delcotron mounting bracket thru delcotron to cylinder head at pivot location 35
Starting motor to block 35
Starting motor brace to block 11
Starter motor brace to starting motor 11
Distributor hold down clamp 13
Automatic Lower Flywheel Housing plate 4
Flywheel housing to cylinder block 35
head torque pattern, Buick 350 to 1969
Head bolt torque pattern for Buick 350 to 1969.
head torque pattern, Buick 350 from 1970
Head bolt torque pattern for Buick 350 from 1970.

GENERAL SPECIFICATIONS

  350-2 350-4 350-4
Code number prefix SO SB SP
Engine type
90° V8
Bore and stroke 3.80 x 3.850 3.80 x 3.850 3.80 x 3.850
Piston Displacement 350 Cu. In. 350 Cu In. 350 Cu. In.
Carburetor type 2 barrel 4 barrel 4 barrel
Compression ratio 9.0:1 9.0:1 10.25:1
Gasoline requirements regular regular premium
Brake horsepower @ RPM 230/4400 285/4600 315/4800
Maximum torque @ RPM 350/2400 375/3200 410/3200
Taxable horsepower 46.2 46.2 46.2
Octane requirements motor 85 85 90
Octane requirements research 93 93 99
Cylinder numbers front to rear
Left bank 1-3-5-7 1-3-5-7 1-3-5-7
Right bank 2-4-6-8 2-4-6-8 2-4-6-8
Firing Order 1-8-4-3-6-5-7-2 1-8-4-3-6-5-7-2 1-8-4-3-6-5-7-2




Piston and pin specifications:
Piston
Material Cast aluminum alloy
Type Divorced skirt
Finish Cam ground
Piston Pins
Material Extruded SAE-1018
Type Pressed in rod

Connecting rods:
Material Pearlitic malleable iron forged - SAE-1053 steel
Rod bearing Removable steel backed M/400 aluminum

Ring specifications:
#1 compression Cast iron-molybdenum coated
#2 compression Cast iron-lubricated
Oil control Steel-uncoated
Oil ring expander Hump type
Ring locations Above pin

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

Camshaft specifications:
Material Cast alloy iron
Bearings Steel backed Babbitt
Number of bearings 5
Drive Chain
Number of links 54
Crankshaft sprocket Sintered Iron
Camshaft sprocket Nylon coated aluminum

Valve specifications:
Intake valve material SAE 1041 steel - Aluminized Face and Chrome Flashed Stem
Exhaust valve material 21-2 Aluminized Face and Chrome Flashed Stem
Valve lifter mechanism Hydraulic
Valve spring Single helical

Lubrication system specifications:
Type of lubrication
Main bearings Pressure
Connecting rods Pressure
Piston pins Splash
Camshaft bearings Pressure
Timing chain Splash and nozzle
Cylinder walls Splash and nozzle
Oil pump type Gear driven
Normal oil pressure 37lbs. @ 2400 RPM
Oil pressure sending unit Electrical
Oil intake Stationary
Oil filter system Full flow
Filter type Throw away element and can
Crankcase capacity
With filter 5qts.
Less filter 4qts.

Cooling system specifications:
System type Pressure
Radiator cap relief pressure 15 PSI
Thermostat Choke type opening at 190°
Water pump
Type Centrifugal
GPM @ RPM 10 @ 1000
Drive V-Belt
Bearings Double row
By-pass recirculation type External

Cooling system capacities:
  (350 Cu. In. "A") (350 Cu. In. LeSabre)
With heater 16.5qts. 16.2qts.
With air conditioning 15.5qts. 16.6qts.

Fan diameter and number of blades:
350 Less AC 18" x 4
350 With AC 18" x 7
Fan Drive
Less AC Water pump shaft
With AC Torque and temperature sensitive clutch

ENGINE DIMENTIONS AND FITS
General:
Piston Clearance limits
Top land .027-.036
Skirt- Top .0008-.0014
Skirt- Bottom .0013-.0029
Ring groove depth
#1 compression ring .1855-.1930
#2 compression ring .1880-.1955
#3 Oil ring .1880-.1955
Ring width
#1 compression ring .0770-.0880
#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 length 3.060
Diameter of pin .9394-.9397
Clearance
In piston .0001-.0004
In rod .00075-.00125 Press
Direction and amount off set in piston .040 major thrust side
*All measurements are in inches unless otherwise specified

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

Crankshaft specifications:
End play at thrust bearing .003-.009
Main bearing journal diameter, 300 2.9995
Crank pin journal diameter 2.0000
Main bearing overall length
#1 .864
#2 .864
#3 1.057
#4 .864
#5 .864
Main bearing to journal clearance .0004-.0015

Camshaft specifications:
Bearing journal diameter
#1 1.785-1.786
#2 1.785-1.786
#3 1.785-1.786
#4 1.785-1.786
#5 1.785-1.786
Journal clearance in bearings .005-.0035 (#2, #3, #4, & #5)

Valve system specifications:
Rocker arm ratio 1.55 to 1
Rocker arm clearance on shaft .0022-.0037
Valve lifter diameter .8422-.8427
Valve lifter clearance in crankcase .0008-.0023
Valve lifter leak down rate 12 to 60 sec. In test fixture
Intake valve
Overall length 5.024 - 4.994
Head diameter 1.880-1.870
Seat angle 45°
Stem diameter (top) .3725 ± .0005
Clearance in guide .0015 - .0025 & .0003 max taper
Valve Stem Height  
Valve spring
Valve closed- Pounds @ length 75 ± 5 @ 1.727
Valve open- Pounds @ length 180 ± 7 @ 1.340
Exhaust Valve
Overall length 5.044 - 5.014
Head diameter 1.505 - 1.495
Seat angle 45°
Stem diameter .3723 Min. and .3730 Max.
Clearance in guide .0015 -.0032 & .0002 max. taper
Valve Stem Height  
Valve spring
Valve closed- Pound @ length 75 ± 5 @ 1.727
Valve open- Pound @ length 180 ± 7 @ 1.340
Valve stem, installed height  

Cubic Inches 350
Bore 3.800
Stroke 3.850
Rod Length 6.387
Rod / Stroke Ratio 1.6514
Bore / Stroke Ratio 0.9870
Bore Spacing 4.240
Deck Height 10.187
Bore Center 4.240