IMPORTANT: Due to the number of applications and years that the LT-1 Distributor is used on, it is highly
recommended to have the Service Manual for your vehicle during this installation.
IMPORTANT NOTES BEFORE INSTALLATION
Throughout its
course, the GM
LT-1engine used
two
different
drive
mecha-
nisms to con-
nect the cam to
the
distributor.
Figure 1 shows
the drive for the
MSD PN 8381
Distributor. This
design is used in
the early model distributors. Make sure this is correct for your application.
Before removing the distributor it is recommended to mark the location of the rotor. This is to ensure
that the distributor and cam are indexed correctly prior to reassembly.
Be sure that the O-ring between the distributor cap and the housing is in place before installing the
cap. The O-ring must be stretched out, then installed onto the housing. It will shrink back to size.
TIMING INFORMATION
Since the timing of the MSD Pro-Billet Distributor can be adjusted, it is recommended that a timing indicator
and mark be fabricated prior to installing the distributor. This way, the timing can be recorded so the MSD
Distributor can be set to the same amount. From the factory,
the MSD Distributor is set to the OEM specs (one and a half
turns).
The MSD Distributor can alter the /-6°, with a quar-
ter turn equalling 1° of timing. The adjusting screw has a soft
Loctite compound applied to it for a seal (Figure 2). Repeated
adjustments may loosen the screw. If this occurs, remove the
screw and apply Blue Loctite
®
to the threads. The screw can
safely be removed from the distributor.
Too much advance may cause detonation resulting in the
ECU retarding the timing through the engine’s knock sensor.
When adjusting the timing, take note that the ECU varies
the timing at an idle. It is recommended to bring the engine
rpm up to 1,500 - 2,000 when setting the timing.
MSD Pro-Billet LT-1 Distributor
'93-'94 F-Body, '92-'94 Corvette, '92-'94 Full Size
PN 8381
Parts Included:
1 - Distributor
1 - Cap
1 - Rotor
1 - Isolator
2 - Rotor Screws
1 - O-ring
3 - 1/4-20 x 2" Socket Head Cap Screws
5 - 8-32 x 0.5" Phillips Screws
1 - Vacuum Line Assembly
1 - Removal Tool
Figure 2 Adjusting the Timing.
Figure 1 The Drive Mechanism of the PN 8381 Distributor.
TIMING
ADJUSTER
CAMSHAFT
STOCK DISTRIBUTOR
INDEX
FLAT
SPOT
INDEX
M S D
• W W W . M S D P E R F O R M A N C E . C O M • ( 9 1 5 ) 8 5 7 - 5 2 0 0 • F A X ( 9 1 5 ) 8 5 7 - 3 3 4 4
ONLINE PRODUCT REGISTRATION: Register your MSD product online and you’ll be entered in our
monthly 8.5mm Super Conductor Spark Plug Wire give-away! Registering your product will help if there
is ever a warranty issue with your product and helps the MSD R&D team create new products that you
ask for! Go to www.msdperformance.com/registration.
