Chevrolet 1979 Light Duty Truck Owner's Manual page 82

FUEL REQUIREMENTS (Gasoline Engines)
(If your truck has a diesel engine, see your Diesel Engine Supplement.)
Your
Light Duty Emission Class Vehicle
chart below) is designed to use
gasoline must be used for proper emission control system operation.
Its use will also minimize spark plug fouling and extend engine oil life.
Using leaded gasoline can damage the emission control system and
could result in loss of emission warranty coverage.
Use unleaded gasoline meeting Federal Government regulations. The
Federal Government specifies the minimum octane number of
unleaded gasoline. Federal regulations require that pumps delivering
such gasoline be labeled with the word UNLEADED. Only these
pumps are equipped with delivery nozzles which fit the filler neck of
your vehicle's gasoline tank.
Your
Heavy Duty Emission Class Vehicle
below) is certified to meet all applicable emission requirements on
regular grade leaded gasoline. The engine does not require
premium grade fuel, so its use would be an unnecessary expense.
If persistent knocking is experienced with regular grade gasoline,
consult your dealer. Excessive knocking may result in engine
damage. Failure to take steps to stop such knocking is misuse
of the engine, and the manufacturing division is not responsible
for any resultant damage under the terms of the new vehicle
warranty.
Unleaded gasoline may be used infrequently in your vehicle if
regular grade leaded fuel is not available at a particular location,
but should not be used exclusively. In addition, the octane level
of unleaded fuel is not always as high as current regular grade
leaded fuel, so a greater tendency to knock may result. "
&
L I G H T
C- K 1 0-20 P I C K- U P
C- K 1 0-20- SU B U R BAN
C-K 1 0 B LAZER
P20 VAN
EM ISSION SYST E M
C-K 20 CAB CHASS I S W I TH H EAVY D UTY EM I S S I O N
OPT I O N
C-K 3 0 PI CK-UP
P1 0 VAN
P20 VAN
SYST E M
P30 VAN
H EAVY DUTY E M I SSI O N C LASS V E H I C L ES
L I GHT DUTY E M I SSION
&
CAB CHASSIS ( E XCEPT C-K 20
CAB C H ASS I S WITH H EAVY DUTY
E M I SS I O N OPT I O N )
&
F/C CHASS I S WITH CA LI F O RN I A
H E AVY DUTY E M I SSION
&
C A B CHASSIS
&
F/C CHASSI S
&
F/C CHASS I S W I T H STAN D A R D E M I SS I O N
&
F / C CHASSI S
only u nleaded
5-2
gasoline engine
gasoline. Unleaded
engine (see chart
(see