1968 Plymouth Valiant Specifications

The Dodge Dart is similar but has a longer wheelbase and length. These figures are from the AMA.

Note: Valiant 100 was coded VL, Signet was coded VH. Two door sedans were coded 21, four-doors 41. Together, they created codes such as VL21 and VH41.

1968 Plymouth Valiant Dimensionsdart/valiant sign

Dimensions 6-cyl V-8
Track – front 57.4 57.4
Track – rear 55.6 55.6
Maximum overall car width 71.0 71.0
Body width at No. 2 pillar 69.6 69.6
Length 6-cyl V-8
Body “O” to front of dash .48 .48
Wheelbase 108 108
Overall car length 188.4 188.4
Overhang – front 31.2 31.2
Overhang – rear 49.2 49.2
Body upper structure length 94.2 94.2
Body “O” line to CL of rear wheel 94.2 94.2
Body “O” line o w/s cowl point 10.8 10.8
Height 6-cyl V-8
Overall height 53.7 54.0
Cowl height 36.3 36.6
Deck height 34.5 34.8
Rocker panel-front to ground 7.5 7.8
Rocker panel-front from front wheel 29.3 29.3
Rocker panel-rear to ground 6.1 6.4
Rocker panel-rear from front wheel 24.2 24.2

Ground clearance

  6-cyl V-8
Bumper to ground – front 11.3 11.7
Bumper to ground – rear 10.9 11.1
Angle of approach 23.6 24.2
Angle of departure 13.8 14.2
Ramp breakover angle 12.0 12.6
Min. running clearance (specify) 5.6 (Frame) 5.9 (Frame)

Interior space

Front Compartment All
Effective head room 38.4
Max. effective leg room at accelerator 41.7
H point to Heel Point 8.9
H point travel 4.5
Shoulder Room 55.4
Hip Room 57.2
Rear Compartment
H point couple distance 32.1
Effective Head Room 37.3
Min. Effective leg room 34.5
H point to heel point 11.1
Min. Knee room 2.1
Rear Compartment room 25.8
Shoulder Room 55.4
Hip Room 57.2
Trunk: Usable luggage capacity 14.5

1968 Plymouth Valiant and Powertrain (Dodge Dart was identical but had extra optional engines)

6-cyl Std axle ratio 6-cyl Opt axle ratio V-8 Std axle ratio V-8 Opt axle ratio
Manual 3-speed 3.23*, 3.55, 2.93 3.23*, 3.55 2.93*, 3.23* 3.23*
Automatic 2.76*, 3.23*, 3.55, 2.93* 2.76*, 3.23*, 3.55, 2.93* 2.93*, 3.23* 2.76, 3.23*
Manual 4-speed - - 3.23*, 3.55**, 3.91* 3.23*, 3.55**, 3.91**

Axle ratios marked with a single asterisk (*) were available in Sure-Grip; those marked with a double asterisk (**) were available only in Sure-Grip.

Engines 6-cyl Std 6-cyl Opt V-8 Std V-8 Opt
Carburetor Single barrel Single barrel Two barrel Two barrel
Type, no. cyls., valve arr. Six, in-line, OHV Six, in-line, OHV 90°, V-8 90°, V-8
Bore and Stroke (nominal) 3.4 x 3.125 3.4 x 4.125 3.63 x 3.31 3.91 x 3.31
Piston displacement, cu. in. 170 225 273 318
Bore spacing (CL to CL) 3.98 (1-2, 3-4, 5-6);
4.0 (2-3, 4-5)
3.98 (1-2, 3-4, 5-6);
4.0 (2-3, 4-5)
4.46 4.46
No. system (front to rear) L. Bank - - 1-3-5-7 1-3-5-7
No. system (front to rear) R. Bank - - 2-4-6-8 2-4-6-8
Firing Order 1-5-3-6-2-4 1-5-3-6-2-4 1-8-4-3-6-5-7-2 1-8-4-3-6-5-7-2
Compres. Ratio (nominal) 8.5 8.4 9.0 9.2
Cylinder Head Material Cast iron Cast iron Cast iron Cast iron
Cylinder Block Material Cast iron Cast iron Cast iron Cast iron
Cylinder Sleeves None None None None
Number of mounting points (Front) Two Two Two Two
Number of mounting points (Rear) One One One One
Engine Installation Angle Lateral 0°, Up 3° Lateral 0°, Up 3° Lateral 0°, Up 3° Lateral 0°, Up 3°
Taxable Horsepower 27.7 27.7 42.2 48.9
Publishing max. bhp* @eng. RPM 115@4400 145@4000 190@4400 230@4400
Publishing max. torque * (lb. ft. @RPM) 155@2400 215@2400 260@2000 340@2400

* Max. bhp (brake horsepower) and max. torque corrected to 60°F and 29.92 in. Hg atmospheric pressure. All cars ran on regular (89) octane leaded fuel.

Pistons

Pistons were aluminum alloy; they were a closed slipper-type, steel strut, ellipitcally-turned, and tin-plated.

Model 170 (6-cyl) 225 (6-cyl) 273 (V-8) 318 (V-8)
Weight (piston only ) oz. 16.4 16.4 19.3 20.9
Clearance (limits) Top land .024 min. .024 min. .017 min. .018 min.
Clearance (limits) Skirt Top .0005 - .0015 .0005 - .0015 .0005 - .0015 .0005 - .0015
Clearance (limits) Skirt Bottom -.0005 - +.0005 -.0005 - +.0005 -.0005 - +.0005 -.0005 - +.0005
Ring groove depth No. 1 and No. 2 ring .179 .179 .191 .205
Ring groove depth No. 3 ring .181 .181 .182 .193

Rings

From top to bottom, ring #1 and #2 were for compression, #3 was for oil. Compression rings were cast iron, lubrite-coated; all #2 rings had reverse twist and taper. Compression width was 0.078 and gap was 0.010 - 0.020. Oil ring width was 0.188.

Model 170 (6-cyl) 225 (6-cyl) 273 (V-8) 318 (V-8)
Compression Twist and taper, tin-plated Twist and taper, tin-plated Twist and radius-faced, tin-plated Twist and radius-faced, tin-plated
Oil Rings Cast iron, steel expanders 3-piece abutment-type, stainless steel spacer-expander with chrome-plated segments 3-piece abutment-type, stainless steel spacer-expander with chrome-plated segments 3-piece abutment-type, stainless steel spacer-expander with chrome-plated segments

Piston pins

All were made from carbon steel - carburizing grade.

Model 170 (6-cyl) 225 (6-cyl) 273 (V-8) 318 (V-8)
Length 2.965 2.965 2.815 2.995
Diameter .9008 .9008 .9842 .9842
Type (Locked in rod, in piston, floating, etc.) Press-fit in rod Press-fit in rod Floating Floating
Type (Bushing, in rod or piston) None None Rod Rod
Type (Bushing, material) - - Bronze on steel Bronze on steel
Clearance (In piston) .00045 to .00075 .00045 to .00075 .0000 to .0005 .0000 to .0005
Clearance (In rod) .0007 to .00014 interference .0007 to .00014 interference .0001 to .0006 .0001 to .0006
Direction & amount offset in piston Right .06 Right .06 Right .06 Right .06

Mopar engine connecting rods

Connecting rods were made of drop-forged steel.

Model 170 (6-cyl) 225 (6-cyl) 273 (V-8) 318 (V-8)
Weight (oz.) 25.7 26.8 25.6 25.6
Length (center to center) 5.707 6.699 6.123 6.123
Bearing (material & type) Lead-based babbitt on steel Lead-based babbitt on steel Bi-metal grid Bi-metal grid
Bearing (overall length) .985 .985 .843 .843
Bearing (clearance [limits]) .0002 to .0022 .0002 to .0022 .0002 to .0022 .0002 to .0022
Bearing (end play) .006 - .012 .006 - .012 .006 - .014 (2 rods) .006 - .014 (2 rods)

Crankshafts: slant six and LA V8

  Slant Six 273 and 318 V8
Material Drop-forged steel Cast ductile iron
Vibration Damper Type Non-adhesive, rubber, dynamic Non-adhesive, rubber, dynamic
End thrust taken by bearing (No.) Three Three
Crankshaft end play .002 - .007 .002 - .007
Main bearing (material & type) Lead-base babbitt on steel, removable, precision Lead-base babbitt on steel, removable, precision
Main bearing (clearance) .0002 - .0022 specified,
.0005 - .0015 desired
.0002 - .0022 specified,
.0005 - .0015 desired
Main bearing (Journal dia. and bearing overall length) No. 1 2.75 x 1.034 2.5 x 0.872
Main bearing (Journal dia. and bearing overall length) No. 2 2.75 x 1.034 2.5 x 0.872
Main bearing (Journal dia. and bearing overall length) No. 3 2.75 x 1.254 2.5 x 1.151
Main bearing (Journal dia. and bearing overall length) No. 4 2.75 x 1.034 2.5 x 0.872
Main bearing (Journal dia. and bearing overall length) No. 5 - 2.5 x 1.562
Crankpin journal diameter 2.187 2.125

Dodge Dart and Plymouth Valiant Camshafts

Model Slant Six 273 and 318 V8
Location Right Center of “V”
Material Hardenable cast iron, oil pump & distributor drive gear cast integrally
Bearings (Material) Lead-base babbitt on steel Lead-base babbitt on steel
Bearings (Number) Four Five
Type of drive (gear or chain) Chain Chain
Type of drive (crankshaft gear or sprocket material) Malleable cast iron or sintered iron (Super Oilite)
Type of drive (camshaft gear or sprocket material) Cast iron Nylon-coated aluminum

Valves

Model Slant Six 273 and 318 V8
Lifters Mechanical Hydraulic
Valve Rotator, type (intake, exhaust) Low-friction lock on exhaust Low-friction lock on exhaust
Rocker ratio 1.5 1.5
Operating tappet clearance (Intake) .010 hot Hydraulic
Operating tappet clearance (Exhaust) .020 hot Hydraulic
Timing (Intake – opens [°BTC]) 10 10
Timing (Intake – closes [°ABC]) 50 50
Timing (Intake – duration –deg.) 240 240
Timing (Exhaust – opens [°BBC]) 50 58
Timing (Exhaust – closes [°ATC]) 6 10
Timing (Exhaust – duration –deg.) 236 248
Timing (Valve opening overlap) 16 20
Intake (Overall length) 4.77 4.98
Intake (Actual overall head dia.) 1.62 1.78
Intake (Angle of seat & face, deg) Seat: 44.5 – 45;
valve: 45 – 45.5
Seat: 44.5 – 45;
valve: 45 – 45.5
Intake (Seat insert material) None None
Intake (Stem diameter) .372 - .373 .372 - .373
Intake (Stem to guide clearance) .001 - .003 .001 - .003
Intake (Lift [@zero lash]) .394 .372
Intake (Outer spring press. & length – valve closed, lb@in.) 62 @ 1.65 92 @ 1.65
Intake (Outer spring press. & length – valve open, lb@in.) 154 @ 1.26 185 @ 1.28
Intake (Inner spring press. & length – valve closed, lb@in.) None None
Intake (Inner spring press. & length – valve open, lb@in.) None None
Exhaust (Material) 21 – 4N 21 – 4N
Exhaust (Overall length) 4.80 5.00
Exhaust (Actual overall head dia.) 1.36 1.50
Exhaust (Angle of seat & face, deg) 47 – 47.5 Seat: 44.5 – 45; valve: 45 -45.5
Exhaust (Seat insert material) None None
Exhaust (Stem diameter) . 371 - .372 . 371 - .372
Exhaust (Stem to guide clearance) .002 - .004 .002 - .004
Exhaust (lift [@zero lash]) .390 .400
Exhaust (Outer spring press. & length – valve closed, lb@in.) 62 @ 1.65 92 @ 1.65
Exhaust (Outer spring press. & length – valve open, lb@in.) 154 @ 1.26 192 @ 1.26
Exhaust (Inner spring press. & length – valve closed, lb@in.) None None
Exhaust (Inner spring press. & length – valve open, lb@in.) None None

Engine lubrication

Piston pins and cylinder walls were given a metered jet spray; pressure lubrication was used on main bearings, connecting rods, cam bearings, and, on V8s only, tappets (slant sixes had splash lubrication for tappets). Normal oil pressure was 45-65 psi at 2,000 rpm. The oil pressure sending unit was electrical; the oil intake was stationery, and the fuel filter was full-flow.

1968 Valiant Exhaust specifications

Model Slant Six 273 and 318 V8
Type (single, single w/cross-over, dual, other) Single Single w/cross-over
Muffler One, reverse flow One, reverse flow
Exhaust pipe dia. – O.D., wall thick. (Branch) - 1.75 x .075
Exhaust pipe dia. – O.D., wall thick. (Main) 1.88 x .075 2.00 x .075
Tail pipe dia. (O.D. & wall thickness) 1.75 x .043 1.88 x .043

Crankcase ventilation systems

All engines used induction-stype crankcase ventilation, with a cylinder-head cover outlet, controlled by a variable orifice; it took air in from the air cleaner (via a tube going to the oil filler cap) and discharged at the intake manifold, at or below the carburetor base. A check valve acted as a flame arrestor.

Every 6 months, owners were to inspect the crankcase ventilator valve, oil filler pipe cap, and associated hoses, clean the oil filler cap, and test the ventilator valve for proper operation; the crankcase ventilator valve was to be replaced every year.

Fuel systems and carburetors

All models used an 18 gallon (US) tank, with a filler outside the left rear fender; the fuel pump was mechanical, with pressure of 3.5 to 5 psi for slant six, and 5 to 7 psi for V8s. Both a fuel tank and fuel supply filters were used. Carburetors had separate automatic chokes, with heat control from the exhaust.

  170 225 273 318
Idle speed – Manual* 750 650 700 650
Idle speed– Automatic* 750 650 650 600
Idle air-fuel mixture* 14.0 – 14.4 14.0 – 14.4 14.0 – 14.4 14.0 – 14.4
Transmission Manual, Automatic Manual, Automatic Manual, Automatic Manual, Automatic
Carburetors (Make) Ball and Ball** Holley Ball and Ball** Ball and Ball**
Carburetors (Model) BBS-4414 S (Manual), BBS-4415 S (Automatic) R-3919 A (Manual), R-3920 A (Automatic) BBD-4416 S (Manual), BBD-4417 S (Automatic) BBD-4420 S (Manual), BBD-4421 S (Automatic)
No. used and type 1, 1-bbl 1, 1-bbl 1, 2-bbl 1, 2-bbl
Barrel Size 1.56 (Manual), 1.69 (Automatic) 1.69 1.44 1.44

* Air conditioner off, transmission in neutral.

** Ball and Ball, a supplier to Chrysler from antiquity, was acquired by Carter, which renamed its carburetors “BBD.”

Timing

170 Manual 170 Auto. 225 Manual 225 Auto. 273 Manual 273 Auto. 318 Manual 318 Auto.
Timing (Degrees) 5 ATC 2.5 ATC TDC TDC 5 ATC 2.5 ATC 5 ATC 2.5 ATC
Timing (@RPM) 700 700 650 650 700 650 650 600
Distributor 2875199 2875202 2875364 2875366 2875334 2875334 2875342 2875342

Spark advance

Distributor Part No. Centrifugal Advance (Crank ° @ RPM) Vacuum Advance (Crank ° @ Inches of Mercury)
Start Intermediate Maximum Start Intermediate Maximum
2875199 0 @ 700-1000 0-7.4 @ 1000, 24.4-28 @ 1980 34-38 @ 4400 0 @ 5-7.1 6-12 @ 8.5 12-17 @ 10
2875202 0 @ 700-1000 0-13.4 @ 1000, 18.4-22.4@1420 28-32 @ 4400 0 @ 5-7.1 6-12 @ 8.5 12-17 @ 10
2875334 0 @ 700-1000 0-14 @ 1000, 22.5-26.5@1470 31-35 @ 3800 0 @ 5-8 10-16 @ 10 21-27 @ 13.5
2875342 0 @ 650-950 0-10 @ 950, 15.5-19.5@1400 36-40 @ 4700 0 @ 8.1-9.8 8-14 @ 12.2 16.5-21.5 @ 15
2875364 0 @ 700-1000 0-7.4 @ 1000, 18.4-22.4@1740 25-29 @ 4000 0 @ 6.2-9.7 4-10 @ 11.9 7.4-12.4 @ 13.8
2875366 0 @ 700-1000 0-7.4 @ 1000, 18.4-22.4@1740 25-29 @ 4000 0 @ 5-7 5-11 @ 8 7.4-12.5 @ 8.7

Manual transmission

All clutches were dry-plate, with oil pressure plate springs, and a facing of woven asbestos. Release bearings were permanently lubricated ball bearings. Torsion damping was done by coil springs with friction washers.

Clutch Slant Six 273 and
slant six optional
318 3-speed 318 4-speed
Make & Type Auburn Auburn Borg & Beck Borg & Beck
Type Pressure plate springs Coil Coil Coil Coil
Total spring load (lb.) min. 1330 1600 1992 2345
Clutch Facing and Area
9.25 x 6.0 / 77.8

9.5 x 6.5 / 75.4

10.0 x 6.0 / 100.5

10.5 x 6.5 / 106.8
Clutch Facing Thickness .114 .114 .130 .125
Engagement cushioning method Two-piece cushion Two-piece cushion Flat wave springs Flat wave springs

Suspension

All models used torsion-bar suspension, adjustable via anchor bolt; brake dip and acceleration squat was controlled by inclined upper control arms and asymmetrical rear springs. Shock absorbers were direct-acting and made by Chrysler, with a 1-inch piston diameter. The front suspension was independent, with non-parallel control arms. Torsion bars were made of chromium alloy steel. A 0.88-inch diameter link-type front stabilizer was optional.

Front ball joints were to be lubricated every three years or 36,000 miles and inspected twice a year. Lubricant was P/N 2525035.

The rear suspension used parallel, longitudinal leaf springs, of a semi-elliptical, asymmetrical design, made of chromium alloy steel. They were 55 inches long and 2.5 inches wide in each case. The spring rate was 85 lb/square inch (105 at the wheel) on all but the 318, which used a 110 lb/square inch rate (132 at the wheel). Rubber mountings were used; Chrysler warned not to lubricate the rear springs, spring eye or shackle bushings, or shock absorber bushings.

Suspension details 170 225 273 318
Front spring height by diameter 35.8 x 0.83 35.8 x 0.83 35.8 x 0.85 35.8 x 0.87
Spring – Rate at wheel (lb. per in.) 85 85 92 99
Number of leaves in rear springs 4 5 4.5 6

Steering details

Manual steering was standard, power steering optional.

Wheel diameter 16.0
Turning diameter (ft.) – Outside Front (Wall to Wall) 40.5
Turning diameter (ft.) – Outside Front (Curb to Curb) 37.8
Turning diameter (ft.) – Inside Rear (Wall to Wall) 21.9
Turning diameter (ft.) – Inside Rear (Curb to Curb) 22.6
Outside whl. Angle with inside whl. at 20° 18°
Steering spindle & joint type Ball joint
Steering type Recirculating ball
Maker of steering system Chrysler
Manual steering gear ratios Std: 24.0 to 1; Opt: 16.0 to 1
Manual overall steering gear ratios Std: 28.7 to 1; Opt: 19.15 to 1
Manual number of wheel turns Std: 5.3; Opt: 3.6
Power steering gear ratios 15.7 to 1
Power steering overall gear ratios 18.8 to 1
Power steering, number of wheel turns 3.5
Steering linkage Parallelogram with two equal length tie rods
Drag link Transverse center link
Steering axis: inclination at camber 7.5° @ 0°
Thrust bearings Oil impregnated sintered metal
Brakes Disc only for V8; drum or disk for slant six
Spindle inner bearing diameter Drum 1.0619; Disc 1.2494
Spindle outer bearing diameter Drum 0.6869; Disc 0.7494

Wheel alignment (range at curb weight and preferred)

Caster (deg.) Manual strg: -0.5°~+mn~0.5°; Power strg: +0.75°~+mn~0.5°
Camber (deg.) Left: +0.5°~+mn~0.25°, +0.5° preferred; Right: +0.25°~+mn~0.25°, 0.25° preferred
Toe-in (outside track inches) 3/32” to 5/32”, 1/8” preferred

 

  170 Slant Six 225 Slant Six 273 V8 318 V8 340 V8
(Barracuda)
383 V8
(Barracuda)
Gross Horsepower 115 hp at 4400 rpm 145 hp at 4000 rpm 190 hp at 4400 rpm 230 hp at 4400 rpm 275 hp at 5000 rpm 290 hp at 4400 rpm
Torque, lbs.-ft. 155 at 2400 rpm 215 at 2400 rpm 260 at 2000 rpm 340 at 2400 rpm 340 at 3200 rpm 390 at 2800 rpm
Compression ratio 8.5 to 1 8.4 to 1 9.0 to 1 9.2 to 1 10.5 to 1 9.2 to 1
Carburetor type 1-bbl. 1-bbl. 2-bbl. 2-bbl. 4-bbl. 2-bbl.
Air cleaner type Silenced Silenced Silenced Silenced Unsilenced Silenced
Exhaust Single Single Single Single Dual Single
Camshaft Standard Standard Standard Standard Special Special
Fuel Regular Regular Regular Regular Premium Regular