PN8572 Datasheet, PDF (1/8 Pages) Mallory performance club – MSD Pro-Billet Chevrolet V8 Tach Drive Distributor

MSD Pro-Billet Chevrolet V8
Tach Drive Distributor
PN 8571
with Vacuum Advance, PN 8572
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Important:  Read these instructions before attempting the installation.
Note: An MSD Ignition is required with this Distributor.
Parts Included:
1 - Pro-Billet Distributor
1 - Rotor, PN 8467
1 - Distributor Cap, PN 8433
1 - Wire Retainer
2 - 1.5" Self Tapping Screws
2 - 10-32 x 3/4" Socket Head Screws
1 - Advance Kit
1 - Gasket
1 - Tube of Gear Lubricant
2 - O-Rings
1 - Vacuum Advance Lock-Out Kit
(PN 8572 Only)
1 - Gear Drive Adapter
WARNING: Before installing the MSD Distributor, disconnect the battery cables. When discon-
necting the battery cables, always remove the Negative (-) cable first and install it last.
Note: The cap of this Distributor requires spark plug style terminals. You may need to change the
terminals and boots of your wires. MSD offers two kits, PN 8849 or PN 8848 that are supplied
with nine boots and terminals. A socket style cap is available as PN 8437.
Note: If the gear is ever replaced, MSD Gear (PN 8531) is required for replacement due to the
.500" diameter shaft.
TIMING FUNCTIONS
Before continuing with the installation, here are a few definitions you should be aware of:
6Initial Timing: This is the base timing (also referred to as idle timing) of the engine before the
centrifugal advance begins.
Centrifugal Advance: The centrifugal (or mechanical) advance mechanism is made up of weights,
springs, advance cams, and an advance stop bushing. The amount and rate of advance that
your distributor is capable of is determined by the centrifugal timing. If you ever wish to lock out
the centrifugal advance, refer to the centrifugal advance section.
Total Timing: This is the total of the initial timing plus the centrifugal advance added together.
Example: 10° Initial + 25° centrifugal = 35° Total Timing (When checking Total timing, disconnect
the vacuum canister and plug the vacuum source).
Vacuum Advance (PN 8572 Only): The vacuum advance will advance the timing up to 10° during
partial throttle driving (with 15 lbs. of vacuum). The vacuum line should be routed to a ported
vacuum outlet above the throttle plates.
Note: MSD Distributors are supplied with the heavy (slow) advance springs installed. This is to
prevent detonation in certain applications. Review the information on pages 2-4 to determine
the best advance curve for your application.
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