Cadillac 60 Series 1963 Shop Manual page 241

10-6 FUEL A N D EXHAUST
2. Loosen two clamps securing muffler.
3. Drive muffler forward until it separates
from front intermediate pipe.
4. Separate muffler from exhaust pipe and re-
move muffler.
b. Installation
1. Install muffler on exhaust pipe. Use floor
jack to support the muffler.
2. Use floor jack to support muffler and install
muffler on front intermediate pipe. Tighten two
clamps securing muffler.
NOTE: Make certain all components are
properly aligned and not contacting frame
members.
3. Remove floor jack.
4. Lower car.
7. Exhaust Pipe
Removal and Installation
a. Removal
1. Raise front end of car.
2. Disconnect exhaust pipe from both exhaust
manifolds and remove heat control valve from
left manifold.
3. Remove clamp at front of muffler.
4. Separate exhaust pipe from muffler and re-
move exhaust pipe,
5. Support muffler on jack stands.
6. Remove all gasket material from heat con-
trol valve and exhaust manifold sealing surfaces.
b. Installation
1. Install exhaust pipe on muffler.
2. Install heat control valve, with gaskets, be-
tween exhaust pipe and left exhaust manifold.
Be sure face of valve stamped "top" is next to
manifold.
3. Connect exhaust pipe, with gaskets, to both
manifolds. Tighten nuts to 33 foot-pounds.
4. Tighten clamp between exhaust pipe and
muffler.
5. Remove jack stands
0
6. Lower car.
8. Heat Control Valve
Removal and Installation
a. Removal
1. Raise front: end of car.
2. Disconnect exhaust pipe from both exhaust
manifolds.
3. Remove heat control valve with upper and
lower gaskets from left manifold.
4. Remove all gasket material from heat con-
trol valve and exhaust manifold sealing surfaces.
b. Installation
1. Install heat control valve, with new gaskets,
and connect exhaust pipe to exhaust manifolds
as described in Note 7b.
2. Lower car.
FUEL SUPPLY SYSTEM
9. Fuel Requirements
To prevent detonation, only premium fuel with
a minimum octane rating of 100 Research Method
and 89 Motor Method should be used. On cars to
be used in foreign countries, where the octane
value of fuel is known to be below 96 Research
Method, the compression ratio must be lowered.
This is accomplished by installing low compres-
sion pistons.
If the Research Method octane rating of availa-
ble fuel is between 96 and 98, install special
cylinder head to block shims, and retard the
spark timing if necessary. Shims and low com-
pression pistons are available through the factory
Parts Warehouse.
Fuels with octane ratings from 98 to 100 by
Research Method may be used, when necessary,
by retarding the spark timing. Engine fuel re-
quirements are reduced by approximately one
octane number for each 2-1/2 degrees that the
spark timing is retarded from the normal 5 de-
gree setting. Do not retard beyond top dead
center.
Altitude above sea level also reduces octane