
GENERAL INFORMATION 0-4
Fig.
 1—Vehicle
 Serial Number
Located on Left Front Hinge
Pillar—Chevrolet Shown 
Fig.
 2—Vehicle Serial Number and
Body Style, Body Number Trim and
Paint Combination Located on
Instrument Panel Brace
Under Glove Box—Corvette 
Fig. 3—Four and Six Cylinder
Engine Unit Number Located on
Pad at Right Hand Side of Cylinder
Block at Rear of Distributor
Fig.
 4—Eight Cylinder Engine Unit
Number Located on Pad at Front,
Right Hand Side of Cylinder Block 
Fig.
 5—Rear Axle Unit Number
Located Bottom Surface of Carrier
at Cover Mounting Flange—Corvette 
Fig.
 6—Rear Axle Unit Number
Located on Right or Left Axle
Tube Adjacent to Carrier
BSHfi^;^
 PAINT
HRIKI5"tM>
 fIHIsS
 HE|St.>MfT*
^^ * *•'"
 •<"'
Fig.
 7—Body Style, Body Number
Trim Type and Paint Combination
Located on Upper Right Hand Side
of the Dash Panel—Chevrol et 
Fig.
 8—Body Style, Body Number
Trim Type and Paint Combination
Located on the Upper Left Hand
Side of the Dash Panel—Chevelle
and Camaro 
Fig.
 9—Body Style, Body Number
Trim Type and Paint Combination
Located on the Upper Right Hand
Part of the Dash Panel—Chevy II
1. Manufacturers identity number assigned to all
Chevrolet built vehicles.
2.
 See Model Identification in this section.
3.
 Last number of model year (1967).
4.
 F-Flint
5.
 Unit numbering will start at 100,001 at all plants.
KEYS AND LOCKS
Four keys (two hexagonal head and two round head) are
provided with each vehicle. The hexagonal-head key
operates the ignition switch and front door locks. The 
round-head key operates the locks for the glove box and
rear compartment lid.
' Lock cylinders (except trunk) are furnished for service
uncoded, this necessitates the coding of these replace-
ment lock cylinders.
NOTE: In service, the trunk and glove box
lock cylinders are provided together with the
trunk lock cylinder coded and the glove box
cylinder uncoded.
The side bar type lock (fig. 18) is used for the ignition,
front doors and trunk. The glove box lock is of the wafer
CHEVROLET CHASSIS SERVICE MANUAL 

GENERAL INFORMATION
 0-6
Once the code number of the lock is obtained look up
this number in a key cutting book.
All side bar locks (except trunk) furnished to the field
by the Parts' Department are uncoded, that is, they are
furnished without tumblers, springs or spring retainers,
these parts are serviced separately. The tumblers come
in five different depths, indicated by numbers.
The side bar locks have six tumbler positions, and in
looking up the cutting code, the following may be used as
an example. After key code number is determined, either
from key or from number stamped on lock cylinder refer
to your code book and record the key cutting information
as follows:
Key of Lock
Code Number
0V11
Cutting or Tumbler
position from head
of lock 
Key Cutting
Code Numerical
545431
123456
NOTE:
 Key blanks used for ignition and door
locks are stamped with an "A" while rear com-
partment and glove box blanks are stamped with
a "B".
The number that is written above the cutting or tumbler
position indicates each different tumbler which is to be
dropped into each tumbier slot of the lock.
In cases where a code book is not available, the dia-
gram shown on Figure 19 may be used to determine the
tumblers required to assemble an uncoded lock cylinder.
1.
 Lay the key on the diagram (fig. 19) with bottom of
key flush with edge of the drawing, head and point
carefully lined up.
2.
 Read the code in numbers 12345 from the head of the
key to the end from positions 1 to 6 inclusive. As
each depth is determined write that number in the
blank space provided above the position numbers
(1-2-3-4-5-6).
3.
 With key properly lined up on diagram, all cuts that
show in the first section are marked
 "1"
 J
4.
 Cuts that fall in the first black section, mark "2".
5. Cuts that fall in the first white section, mark "3".
6. Cuts that fall in second black section, mark "4".
7. Cuts that fall in the second white section, mark "5".
After the numbers have been determined and written
above the cutting positions the lock cylinder should be
assembled as follows.
Lock Cylinder Assembly—Refer to Figure 20
1.
 Hold cylinder with head of cylinder away and starting
•... at the head of the cylinder, insert the tumblers in 
their proper slots in the order called for by the
code, ribbed side toward you and long point down.
2.
 After all tumblers are in place, check for correct-
ness with the code. Then press tumblers down with
one finger.
3.
 Insert one tumbler spring in the space provided
above each tumbler.
CAUTION: If the springs are tangled, do not
pull them apart—unscrew them.
4.
 Reverse the lock cylinder so that the head of the
cylinder is now toward you. Insert the spring re-
tainer so that one of its six prongs enters into each
of the springs and the two large end prongs slide into
the slots at either end of the cylinder. Press the
retainer down with one finger.
5. To check, insert proper key and if tumblers are in-
stalled properly the side bar will be allowed to drop
down. If bar does not drop down, remove the key,
spring retainer, springs and tumblers and reas-
semble correctly.
NOTE:
 If the tumblers have not been assembled
correctly and not according to the code, the
tumblers can be removed from the cylinder by
holding it with the tumbler slots down, pulling
the side bar out with the fingers and jarring the
cylinder to shake the tumblers out. This pro-
cedure is necessary because after the tumblers
have been pressed down into the cylinder they
are held in their slots by the cross bar.
6. If after checking it is found that the lock is as-
sembled properly, remove key and place cylinder in
INSERTING
TUMBLER 
CHECKING
WITH CODE
STAKING
POINTS
NSERTING
TUMBLER SPRINGS 
INSERTING
SPRING RETAINER
Fig.
 19—Tumbler Requirement Diagram 
Fig.
 20—Assembling Lock Cylinder
CHEVROLET CHASSIS SERVICE MANUAL 

HEATER AND AIR CONDITIONING 1A-56
BLACK & RED
IGNITION—-y^****
SWITCH -"A
/
BLOWER LEAD—^^^
RESISTOR—-" \^<
ASM.
 f'
i 
'fu^^^^A^^^^^r"G^OUH£>
 WIRE
^^ 
k4
^EVAPORATOR HARNESS
' EVAPORATOR & BLOWER ASM.
Fig.
 73—Underdash Wiring—Universal System (Typical)
evaporator outlet pipes. Locate the bracket about
1/2" from the dash panel.
12.
 Replace the inlet and outlet hoses and hose clamp
connections.
13.
 Evacuate and charge the system. Add three fluid oz.
refrigerent oil after installing a new core.
14.
 Check system performance.
Corvette
Replacement (Fig. 78)
1.
 Purge the system of refrigerant.
2.
 Drain the engine radiator. Then remove the radiator
supply tank from its brackets, the heater water
valve and vacuum line from the firewall, and the
heater hoses from the core pipes. Carefully fold the
hoses,
 valve and tank away from the evaporator
case.
3.
 Remove the right hand hood lock support. 
SCREW DRIVER
(NARROW BLADE) T£
GROOVE
A. Insert screw driver in
tang toward terminal
B. Pry tang back out to
when reinstalled into 
RMINAL
\ CONNECTOR
TANG
groove & press
to release.
insure locking
connector.
Fig.
 74—Terminal Removal—Universal System
4.
 Disconnect the expansion valve equalizer line con-
nection and the evaporator oil bleed line from the
POA.
5.
 Disconnect the evaporator outlet to POA inlet
connector.
6. Remove the POA bracket to evaporator case attach-
ing bolts. Then carefully move the valve and its
outlet hose away from the evaporator case.
Fig.
 75-Cable Removal-All Weather
CHEVROLET CHASSIS SERVICE MANUAL 

HEATER AND AIR CONDITIONING 1A-73
Fig.
 105—Comfortron Control Head
10.
 Introduce R-12 vapor at cylinder (room) temperature
and pressure.
11.
 Leak test all fittings and connections and give partic-
ular attention to a leak test at the compressor shaft
seal if compressor has not been leak tested on the
bench.
12.
 Complete system processing and charge system.
FUSES
A fuse, located in the junction block protects the entire
air conditioning system except for the blower when op-
erating at high speed.
A second fuse, to protect the high speed blower circuit,
is located in the electrical wiring between the horn relay
and the Air Conditioner relay (except Universal). The 
Universal unit has a fuse in the line between the ignition
switch and the Air Conditioner blower switch. See the
specification page for the proper replacement fuse.
FOUR SEASON HEATER COMPONENTS
Corvette
The heater components of the system are, in general,
much the same as those of the standard Corvette heater.
Heater hoses carry the engine coolant to the heater core,
located in the air distributor duct beneath the instrument
panel.
A significant difference is that in the Corvette Air
Conditioning System there is no flow through the heater
core until the COOL IN-HOT PULL knob is pulled out.
This movement opens the vacuum switch on the air
distributor assembly and allows vacuum to be applied
to the water valve mounted in the engine compartment,
opening the valve. Thus the heater core is unheated
until needed, at which time it receives full flow of the
engine coolant. Air passing through the core receives
maximum heat which is tempered by mixing with un-
heated air before entering the passenger compartment.
Heater Core
Replacement
The heater core in the Corvette Air Conditioning
System is removed in the same manner as the core in
the Corvette heater. The distributor assembly must first
be removed from under the dash as covered previously
in this section before the core can be removed and
replaced.
Water Valve
Installation of the water valve is illustrated in Figure
113.
 An inoperative valve must be replaced.
Chevrolet
Heater Core
Removal
1.
 Disconnect battery ground cable.
2.
 Drain radiator
3.
 Remove right front fender and skirt assembly.
Fig.
 106—Comfortron Temperature Dial Adjustment 
Fig.
 107—Amplifier Removal
CHEVROLET CHASSIS SERVICE MANUAL 

HEATER AND AIR CONDITIONING 1A-81
HORN RELAY
r
CONN.-
14 BROWN
(TO FUSE
PANEL) 
BATTERY 
1
—I ^ COMPR
ESSOR
DASH y
V-^ PANEL \
GROMMET—%
 1 \
_ J~ ") "^
>14 BLACK/RED STRIPE-
FUSE .20 AMP.
•WIRE ASM. BLOWER-
MOTOR 
14 BLACK 1
IGNITION SWITCH1
(ACCESSORY
TERMINAL)
CONTROL SWITCH 
-RESISTOR
CONN.
•14 TAN
•16 BLACK
LIGHT BLUE STRIPE
•THERMOSTAT CONTROL
EVAPORATOR & BLOWER ASM.
Fig.
 117—Universal System Wiring Diagram (Typical)
CHEVROLET CHASSI 

HEATER AND AIR CONDITIONING 1A-82
•BATTERY
(POS)
 CABLE
 NOTE
 When
 control
 switch*
is !TOFF"
 &
 Air
 Cond
 is
 "ON"
(Control
 knob
 pulled
 but) the
blower
 fan'will
 run at low
 speed. 
CONTROL
 SWITCH
CONNECTIONS
OFF
LOW
MED
HIGH 
B
 TO
 NONE
B
 TO L
BTOL&M
B
 TO L
 &
 H
COMPRESSOR
 GROUND
WIRE
 ASM
BATTERY
(NEGATIVE)
CABLE
COMPRESSOR
 ASM
DASHPAJSTEL
GROMMET
16DG 
CONTROL
SWITCH
RESISTOR
ASM
14LBL
14BRN
CLUTCH
COIL
EXTENSION
WIRE
 ASM 
-14BRN--N
JUNC
BLOCKi
OSTATIC
SWITCH
CONTACTS
NORMALLY
CLOSED
STARTING
MOTOR
SOLENOID
BLOWER
MOTOR 
AIR
 COND
CONTROL
(PUSH-PULL)
KNOB
DOOR
 SWITCH
(PUSH
 BUTTON
NORMALLY
CLOSED) 
RELAY
ASM
HORN
RELAY
DIVERTER
DOOR CABLE
FUSE
PANEL
EVAPORATOR
ASM
IGNITION SWITCH-
ACCESSORY TERMINAL)
Fig. 118—All Weather Wiring Diagram (Chevy II)
CHEVROLET CHASSIS SERVICE MANUAL 

HEATER AND AIR CONDITIONING 1A-83
DIVERTER DOOR
CRANK POSITIONS:
AIR COND "ON"
AIR COND "OFF*
AIR COND SWITCH
(PUSH BUTTON,
NORMALLY CLOSED
CONTACTS)
BLOWER MOTOR
CONTACTS
NORMALLY
4D
16
16B/Y
COMPRESSOR
GROUND WIRE
ASM
BAT.
 TERMINAL
ON STARTING
MOTOR SOLENOID
' BATTERY
CABLE ASM:
NEGATIVE
POSITIVE—* 
- CONTROL SWITCH
SET AT:
•OFF
LOW
MED
HIGH 
CONTACTS:
BTOBL
BTOL
BTOM
BT0M6B,
CLUTCH
HOUSING 
liOli: WHEN CONTROL
SWITCH IS AT "OFF" &
AIR COND. IS "ON", FAN
WILL RUN AT LOW SPEED.
"AIR COND-PULL"
KNOB (SHOWN IN "ON"
POSITION)
TO REGULATOR
HORN
RELAY 
16 BRN-BODY WIRING
HARNESS-837
14BRN
I
^
 IA^RN
 * IGNITION SWITCH
« 12R ACCESSORY TERMINAL
12R f
AMMETER
LEGEND:
AIR COND WIRING (PART OF
ENGINE WIRING HARNESS)
WIRING IS PART OF EQUIP
REG PRODUCTION WIRING
Fig.
 119—Corvette—Four-Season Wiring Diagram
CHEVROLET CHASSIS SERVICE MANUAL 

SECTION 6
ENGINE
CONTENTS
 OF
 THIS SECTION
Page
Engine Tune Up
 6-1
 Torque Sequence
Engine Mechanical
 (In
 Line)
 6-12
 Special Tools
 . .
Engine Mechanical (V8)
 6-24 
Page
6-39
6-40
ENGINE TUNE UP
INDEX
Page
General Description
 . 6-1
Mechanical Checks and Adjustments
 6-1
Spark Plug Removal
 6-1
Test Compression
 6-1
Service and Install Spark Plugs
 6-2
Service Ignition System
 6-3
Service Battery
 and
 Battery Cables
 6-5
Service Delcotron
 and
 Regulator
 6-5
Service
 Fan
 Belt
 6-5
Service Manifold Heat Valve
 6-5
Tighten Manifold
 6-5
Service Fuel Lines
 and
 Fuel Filter ..........
 6-6
Service Cooling System
 6-6
Check and Adjust Accelerator Linkage
 6-6
Service Crankcase Ventilation
 6-6
Service
 Air
 Injection Reactor System
 6-6
Choke Adjustment
 6-7 
Page
Instrument Cheek-Out
 6-7
Instrument Hook-Up.
 . 6*7
Check and Adjust Dwell
 6-7
Check Dwell Variation
 6-7
Check and Adjust Timing
 6-8
Adjust Idle Speed
 and
 Mixture
 6-8
Additional Checks and Adjustments
 . 6-8
Testing Crankcase Ventilation Valve
 . 6-8
Testing Cranking Voltage
 6-8
Cylinder Balance Test
 . 6-8
Battery
 6-8
Ignition
 ; 6-8
Carburetor
 6-11
Fuel Pump
 6-11
Cooling System
 . 6-11
Cylinder Head Torque and Valve Adjustment
 ..... 6-11
GENERAL DESCRIPTION
The engine tune up
 is
 important
 to the
 modern automo-
tive engine with
 its
 vastly improved power and perform-
ance.
 The
 higher compression ratios, improved electri-
cal systems
 and
 other advances
 in
 design, make today1 s
engines more sensitive
 and
 have
 a
 decided effect
 on
power, performance and fuel consumption.
It
 is
 seldom advisable
 to
 attempt
 a
 tune up
 by
 correc-
tion
 of one or two
 items only. Time will normally
 be
saved
 and
 more lasting results assured
 if the
 technician
will follow
 a
 definite
 and
 thorough procedure
 of
 analysis
and correction
 of all
 items affecting power, performance
and economy.
The tune
 up
 will
 be
 performed
 in
 two parts.
 The
 first
part will consist
 of
 visual and mechanical checks and
 ad-
justments;
 the
 second part will consist
 of
 an instrument
checkout that
 can be
 performed with
 any one of the
 units 
of service equipment available
 for
 this purpose. Always
follow
 the
 instructions provided
 by the
 manufacturer
 of
the particular equipment
 to be
 used.
Additional checks
 and
 adjustments
 are
 included
 in the
latter part
 of
 this section
 for use as
 required. Many
 of
these operations
 can be
 used
 to
 isolate and correct trou-
ble located during
 the
 tune up. Where conditions
 are
 UB-
covered requiring major corrective action, refer
 to the
appropriate section
 of
 this manual
 or the
 Passenger
Chassis Overhaul Manual
 for
 detailed service informa-
tion.
Typical illustrations
 and
 procedures
 are
 used except
where specific illustrations
 or
 procedures
 are
 necessary
to clarify
 the
 operation. Illustrations showing bench
 op-
erations
 are
 used
 for
 clarification however
 all
 operations
can
 be
 performed
 on the
 vehicle.
MECHANICAL CHECKS
 AND
 ADJUSTMENTS
Spark Plug Removal
Remove any foreign matter from around spark plugs
 by
blowing
 out
 with compressed
 air,
 then disconnect wires
and remove plugs.
Test Compression
 (Fig. 1)
The compression check
 is
 important because
 an
 engine
with
 low or
 uneven compression cannot
 be
 tuned success- 
fully.
 It is
 essential that improper compression
 be cor-
rected before proceeding with
 the
 engine tune
 up.
1.
 Remove
 air
 cleaner
 and
 block throttle
 and
 choke
 in
wide open position.
2.
 Hook
 up
 starter remote control cable
 and
 insert
compression gauge firmly
 in
 spark plug port.
CAUTION: Whenever
 the
 engine
 is
 cranked
CHEVROLET
 C* 
IS SERVICE MANUAL