MSD 83647 HEAT HEI Module Installation User Manual
Msd heat digital hei module, Installation

Figure 1 Installing the Module.
This Module is a performance replacement for GM’s 4-Pin HEI Module. It features a programmable
rev limiter for overrev protection. The Module will mount in a stock HEI housing (by removing the
original condenser assembly) or in MSD’s Pro-Billet HEI Distributor, PN 8365. A GM Coil can be used
or for maximum performance, use MSD’s HEI Coil, PN 8225.
Parts Included:
1 - HEI Module, PN 83647
1 - Tube of Heat Sink Compound
1 - Gray Tach Wire
2 - Mounting Screws and Star Washers
1 - Low Resistance Rotor Bushing, PN 8412
INSTALLATION
1. Mark the location of the spark plug wires on the cap prior to removal.
2. Remove the cap, rotor, module and condenser (if equipped) from the original distributor.
3. Apply a liberal coat of the Heat Sink Compound to the aluminum base of the Module.
4. Route the wiring harness out of the housing and position the short Black wire to ground with one
of the mounting screws (Figure 1).
5. Position the module in the distributor then locate the two screws and star washers to secure the
module (Figure 1).
6. Reinstall the rotor
and cap.
Note: A tachometer is required to program the rev limit.
CONNECT SHORT
BLACK WIRE
TO GROUND
APPLY
HEAT SINK
COMPOUND
DISTRIBUTOR
HOUSING
DIGITAL
HEI MODULE
CAP
CONNECTOR
SCREWS AND
STAR WASHERS
TO TACH
USE TO
PROGRAM TACH
GRAY
TACH
OUTPUT
REV LIMIT
BYPASS
JUMPER
MSD HEAT Digital HEI Module
PN 83647
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