MSD 50901 Installation

MSD DynaForce Starter

FORD 289, 302, 351W

3/4" Depth, PN 5090, 3/8" Depth, PN 50901

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IMPORTANT: Proper installation of the DynaForce Starter is important to the overall operation. Correct alignment

of the starter pinion with the ring gear is needed to achieve the best operation and longevity from
your starter. Please read the instructions before attempting the installation.

Parts Included:

1 - Starter 1 - Shim Ring 1 - Outer Shim

WARNING: Before installing the DynaForce Starter disconnect the battery cables. When disconnecting

the battery cables, always remove the Negative (-) cable first and install it last.

When selecting a starter for your Ford, our research has found that year, model and drivetrain
combination do not always dictate the correct starter. There are variations between the 164 tooth and
157 tooth flywheels and well as the inside diameter of the starter block plate (4.130” or 4.084”). MSD
offers two starters for the 289/302 and 351W engines; one with a 3/8th depth ring gear, one with a
¾” depth. Figure 1 shows the differences and applications.

When using OEM bell housings, it must be paired with the corresponding flywheel and ring gear.
Many aftermarket bellhousings feature a punch out to allow both to be used.

ENGINE BLOCK PLATE

3/4”

TRANSMISSION

3/8”

RING GEAR TEETH TRANSMISSION STARTER REGISTRY DIAMETER DEPTH STARTER

164 4-speed 4.130" 3/8" PN 50901
164 Automatic 4.084" 3/4" PN 5090
157 4-speed and Auto 4.084" 3/4" PN 5090

USE
PN 5090

USE
PN 50901

ENGINE BLOCK PLATE

Note that these are generally the applications, however there are variables.

Figure 1 Ring Gear Depth and Bell Housing/Engine Block Identification.

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

2 INSTALLATION INSTRUCTIONS

INSTALLATION

CLOCKING

LOCATIONS

1. Make sure the starter mounting flange on the mid plate is
clean and smooth.

2. Before mounting the starter, measure the distance from the
front of the ring gear (engine side) to the starter mounting
surface (Figure 2).

• If there is not enough clearance, you will need to install

the supplied shim kit by removing the mounting block
(Figure 3). Place the small shim ring in the bearing bore
and install the outer shim on the support housing. Reinstall
the mounting block. This will move the pinion gear into the

Figure 2 Clocking the Starter for Clearance.

starter approximately 0.060".

3. Check that the position of the solenoid is away
from direct heat sources and other components.
If there are clearance problems, the starter
housing can be rotated to move the location of
the solenoid. This is done by removing the three

SHIM

RING

INSTALL OUTER

SHIM

bolts on the mounting block and repositioning the
starter motor (Figure 1).

4. After confirming clearances and positioning.
Mount the starter.

• If there is not enough clearance, you will need

to install the supplied shim kit by removing the
mounting block (Figure 3). Place the small shim
ring in the bearing bore and install the outer
shim on the support housing. Reinstall the
mounting block. This will move the pinion gear
into the starter approximately 0.060".

• The gear mesh is not adjustable on this

Figure 3 Installing the Pinion Shim Spacers.

application. Verify that all parts are correct for the application (flywheel, block plate, starter) and
verify starter is mounted correctly to engine plate.

5. The switch wire that connects to the solenoid should be at least 12-gauge (Figure 4). For alternative
wiring to incorporate the factory remote solenoid, See Figure 5.

Note: If your original starter had wire going to a second terminal, an ‘R’ terminal, this can generally

be bypassed. See the information on the last page of the instructions for more details.

6. Attach the battery cable. The gauge of the battery cable depends on its length. Using the proper
gauge wire is important to the operation of the starter. Both the positive and ground wires must be
able to meet the demands of the starter. The chart in Figure 5 shows the recommended sizes. Be
sure to route the wire away from the exhaust and moving parts of the engine.

7. Connect the battery terminals and start the engine.

IMPORTANT: Never operate a starter for more than 30 seconds at a time without letting it cool for at

least two minutes.

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