Advance Adapters 712570 - Manual (Page 2)

BELLHOUSING FOR JEEP 4.0 HIGH OUTPUT
6 CYLINDER ENG. TO GM SM420 TRUCK 4SP
INSTALLATION INSTRUCTIONS:
Depending on the year of the vehicle that you are dealing with, you will need to vary the clutch control requirements
accordingly. The bellhousing that we manufacture will use a GM clutch release arm along with a GM clutch release
bearing. Since you are using a GM transmission, the N1430 release bearing and GM clutch release arm will work
perfectly without any modifications. The new GM clutch arm will have an internal snap ring to lock onto the ball pivot
stud inside the new bellhousing. On Jeep vehicles that were originally equipped with a mechanical clutch control, you
should not have any problem adapting your original clutch linkage to the new clutch arm. On Jeep vehicles that were
previously equipped with a hydraulic slave cylinder such as 1987-2005 and 1980-1986 four cylinders, you will need to
use a Jeep slave cylinder that was used in the 1980-1983 Iron Duke four cylinder Jeep vehicles. We offer this Jeep clutch
control slave cylinder kit as Part No. 716331. This new assembly will include all the necessary parts to mount to the
new bellhousing.
The bellhousing is a direct duplicate of the original AMC stock bellhousing. The flywheel sensor, dowel pin holes and
dust cover mounting holes are all in the original location. The original dust cover or block plate must be retained for
use with the Advance Adapter bellhousing. This plate is normally already on the engine block. The flywheel sensor must
be installed onto the new bellhousing using the original bolts or new bolts that we have supplied. These special bolts
provide the necessary accuracy to mount the sensor in the appropriate location.
Your new SM420 transmission will require a new pilot bushing for the engine crank and possibly a new clutch disc. The
SM420 will require a Chevy clutch disc with a 1-1/8"-10 spline size Centerforce No. 384193. It is advisable that you
check the input shaft tip engagement into the new pilot bearing after installation.
DO NOT FORCE THE
TRANSMISSION INTO POSITION. The flywheel must be 1" thick. We have seen some flywheels up to 1.5" thick,
which can cause interference problems. This 1" measurement should be taken from the crank flange to the clutch disc
surface. This bellhousing also requires the use of a diaphragm pressure plate. Most Borg & Beck 3 finger pressure plates
will not work.
Prior to assembling the bellhousing onto the engine, you will need to install the clutch ball pivot. We have provided two
(2) different locations depending on the year of the vehicle that the bellhousing is being installed into. The upper location
will be for Wrangler hydraulic clutch controls, while of the lower location will be for mechanical clutch type controls.
Refer to Page 6 for additional information.
SM420 AND SM465 SHIFT TOWER CLEARANCES:
The new bellhousing will allow for the Chevy transmission to bolt directly against the face. There are a few transmissions
that have the top shifter cover over lapping the face of the transmission. If your transmission has this slight over lap,
it will be necessary to grind a small relief on either the top shifter or bellhousing area.
ADVANCE ADAPTERS INC. P/N: 712570
P.O. Box 247, 4320 Aerotech Center Way
Paso Robles, CA 93447
PAGE 2 OF 6
Telephone: (800) 350-2223 Fax: (805) 238-4201 Page Rev. Date: 07-16-13
SPECIAL NOTE: The components packaged in this kit have been assembled and machined for specific type of conversions. Modifications to any of the components
will void any possible warranty or return privileges. If you do not fully understand modifications or changes that will be required to complete your conversion, we strongly
recommend that you contact our sales department for more information. This instruction sheet is only to be used for the assembly of Advance Adapter components.
We recommend that a service manual pertaining to your vehicle be obtained for specific torque values, wiring diagrams and other related equipment. These manuals are
normally available at automotive dealerships and parts stores.
CAUTION: On some of the early installations, we have encountered an interference problem between
the clutch pressure plate and clutch release arm. The solution is to grind the necessary clearance on the
inside of the bellhousing and modify the release lever approximately 1/16". It will be necessary for your
to check the clutch clearance inside the bellhousing prior to transmission assembly. This problem has only
occurred with aftermarket clutch assemblies or thicker than normal flywheels.