MSD Pro-Billet Chevrolet HEI Distributor PN 8365

Before installing the MSD Distributor, disconnect the battery cables. When disconnecting the battery cables, always remove the Negative (-) cable first and install it last.
TIMING FUNCTIONS
Before continuing with the installation, here are a few definitions you should be aware of:
Initial 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 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.
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. 
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: 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.
TRACTION CONTROL DETECTION
The Extreme Digital HEI Module has a unique Traction Control Detection (TCD) code built into its microprocessor. This technology carefully monitors and examines the signals of the ignition. If the TCD determines that any signal has been modified in any way, the ignition will be put into a low rpm rev limit mode to immediately slow the car. Before this rev limit is imposed, the TCD goes through a list of cycles and checks to qualify that the trigger has been modified. There is no way to bypass or deactivate the TCD circuitry.

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