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 Dimensions

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	170 six	225 (opt)	273	318
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
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
# (front to rear) L. Bank	-	-	1-3-5-7	1-3-5-7
# (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 Sleeves	None	None	None	None
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
Max. bhp* @ RPM	115@4400	145@4000	190@4400	230@4400
Max. torque * (lb. ft.)	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. The head and block were cast iron, without cylinder sleeves.

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.

Ring compression was twist and taper on slant six, twist and radius-faced on V8, tin-plated regardless, Rings were cast iron with steel expanders on the 170 alone; all others were a three-piece abutment-type setup with a stainless steel spacer-expander having 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.

Sixes	170	225
Idle speed – Manual*	750	650
Idle speed– Automatic*	750	650
Idle air-fuel mixture*	14.0 – 14.4	14.0 – 14.4
Carburetors (Make)	Ball and Ball**	Holley
Carburetors (Model)	BBS-4414 S (Manual), BBS-4415 S (Automatic)	R-3919 A (Manual), R-3920 A (Automatic)
No. used and type	Single one-barrel	Single one-barrel
Barrel Size	1.56 (Manual), 1.69 (Automatic)	1.69

V8s	273	318
Idle speed – Manual*	700	650
Idle speed– Automatic*	650	600
Idle air-fuel mixture*	14.0 – 14.4	14.0 – 14.4
Carburetors (Make)	Ball and Ball**	Ball and Ball**
Carburetors (Model)	BBD-4416 S (Manual), BBD-4417 S (Automatic)	BBD-4420 S (Manual), BBD-4421 S (Automatic)
No. used and type	Single two-barrel	Single two-barrel
Barrel Size	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

Six	170 Man	170 Auto.	225 Man	225 Auto.
Timing (Degrees)	5 ATC	2.5 ATC	TDC	TDC
Timing (@RPM)	700	700	650	650
Distributor	2875199	2875202	2875364	2875366

V8	273 Man	273 Auto	318 Man	318 Auto
Timing (Degrees)	5 ATC	2.5 ATC	5 ATC	2.5 ATC
Timing (@RPM)	700	650	650	600
Distributor	2875334	2875334	2875342	2875342

Spark advance

Distributor	Centrifugal Advance (Crank ° @ RPM)
Part #	Start	Intermediate	Maximum
2875199	0 @ 700-1000	0-7.4 @ 1000, 24.4-28 @ 1980	34-38 @ 4400
2875202	0 @ 700-1000	0-13.4 @ 1000, 18.4-22.4@1420	28-32 @ 4400
2875334	0 @ 700-1000	0-14 @ 1000, 22.5-26.5@1470	31-35 @ 3800
2875342	0 @ 650-950	0-10 @ 950, 15.5-19.5@1400	36-40 @ 4700
2875364	0 @ 700-1000	0-7.4 @ 1000, 18.4-22.4@1740	25-29 @ 4000
2875366	0 @ 700-1000	0-7.4 @ 1000, 18.4-22.4@1740	25-29 @ 4000

Distributor	Vacuum Advance (Crank ° @ Inches of Mercury)
Part #	Start	Intermediate	Maximum
2875199	0 @ 5-7.1	6-12 @ 8.5	12-17 @ 10
2875202	0 @ 5-7.1	6-12 @ 8.5	12-17 @ 10
2875334	0 @ 5-8	10-16 @ 10	21-27 @ 13.5
2875342	0 @ 8.1-9.8	8-14 @ 12.2	16.5-21.5 @ 15
2875364	0 @ 6.2-9.7	4-10 @ 11.9	7.4-12.4 @ 13.8
2875366	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°±0.5°; Power strg: +0.75°±0.5°
Camber (deg.)	Left: +0.5°±0.25°, +0.5° preferred; Right: +0.25°±0.25°, 0.25° preferred
Toe-in (outside track inches)	3/32” to 5/32”, 1/8” preferred

The sixes

	170 Slant Six	225 Slant Six
Gross Horsepower	115 hp at 4400 rpm	145 hp at 4000 rpm
Torque, lbs.-ft.	155 at 2400 rpm	215 at 2400 rpm
Compression ratio	8.5 to 1	8.4 to 1
Carburetor type	1-bbl.	1-bbl.
Air cleaner type	Silenced	Silenced
Exhaust	Single	Single
Camshaft	Standard	Standard
Fuel	Regular	Regular

The economy eights

	273 V8	318 V8
Gross Power	190 hp at 4400 rpm	230 hp at 4400 rpm
Torque, lbs.-ft.	260 at 2000 rpm	340 at 2400 rpm
Compression	9.0 to 1	9.2 to 1
Carburetor	2-bbl.	2-bbl.
Air cleaner	Silenced	Silenced
Exhaust	Single	Single
Camshaft	Standard	Standard
Fuel	Regular	Regular

The hot eights

	340 V8 (Barracuda)	383 V8 (Barracuda)
Gross Power	275 hp at 5000 rpm	290 hp at 4400 rpm
Torque, lbs.-ft.	340 at 3200 rpm	390 at 2800 rpm
Compression	10.5 to 1	9.2 to 1
Carburetor	4-bbl.	2-bbl.
Air cleaner	Unsilenced	Silenced
Exhaust	Dual	Single
Camshaft	Special	Special
Fuel	Premium	Regular

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