REMOVAL & INSTALLATION
See Figures 1 and 2
The points-type distributor is used on all 1967-73 and some 1974 models.
- Remove the distributor cap and position it out of the way.
- Disconnect the primary coil wire and the vacuum advance hose.
- Scribe a mark on the distributor body and the engine block showing their relationship. Mark the distributor housing to show the direction in which the rotor is pointing. Note the positioning of the vacuum advance unit.
- Remove the hold-down bolt and clamp, then remove the distributor.
- Reinsert the distributor into its opening, aligning the previously made marks on the housing and the engine block.
- The rotor may have to be turned either way a slight amount to align the rotor-to-housing marks.
- Install the retaining clamp and bolt. Install the distributor cap, primary wire or electrical connector, and the vacuum hose.
- Start the engine and check the ignition timing.
- Turn the engine to bring No. 1 piston to the top of its compression stroke. This may be determined by inserting a rag into the No. 1 spark plug hole and slowly turning the engine over. When the timing mark on the crankshaft pulley aligns with the 0 on the timing scale and the rag is blown out by compression, No. 1 piston is at top-dead-center (TDC).
On Mark IV (big block) V8 engines there is a punch mark on the distributor drive gear which indicates the rotor position. Thus, the distributor may be installed with the cap in place. Align the punch mark 2º clockwise from the No. 1 cap terminal, then rotate the distributor body1/8turn counterclockwise and push the distributor down into the block.
- Install the distributor half-way in the engine block so that the vacuum advance unit points in the correct direction.
- Turn the rotor so that it will point to No. 1 terminal in the cap.
- Install the distributor fully into the engine block. It may be necessary to turn the rotor a little in either direction in order to engage the gears.
- Tap the starter a few times to ensure that the oil pump shaft is mated to the distributor shaft.
- Bring the engine to No. 1 TDC again and check to see that the rotor is indeed pointing toward the No. 1 terminal of the cap.
- After correct positioning is assured, turn the distributor housing so that the points are just opening. Tighten the retaining clamp.
- Install the cap and primary wire. Check the ignition timing. Install the vacuum hose.
See Figure 3
HEI distributors are used on all 1975-81 and some 1974 models.
- Disconnect the ground cable from the battery.
- Tag and disconnect the feed and module terminal connectors from the distributor cap.
- Disconnect the hose at the vacuum advance (1975-80 models only).
- Trace the No. 1 spark plug wire from the spark plug (front spark plug on the left-hand side of the engine) to the distributor cap. Mark the No. 1 spark plug cable terminal on the cap, then matchmark the terminal position on the distributor housing for installation purposes.
- Depress and release the four distributor cap-to-housing retainers and lift off the cap assembly.
- Rotate the crankshaft until the distributor rotor points at the No. 1 spark plug cable terminal mark made in Step 4. The TDC mark on the front damper should also be aligned with the 0 degree mark on the timing mark tab attached to the front of the engine. If the TDC mark is still slightly off, move the crankshaft until it is correctly aligned (this may mean that the distributor rotor is not pointing directly at the No. 1 spark plug cable terminal). At this point the engine is positioned with the No. 1 cylinder at TDC on its compression stroke.
- Using crayon or chalk, make matchmarks on the rotor and module, and on the distributor housing and engine for installation purposes.
- Loosen and remove the distributor clamp bolt and clamp, then lift the distributor out of the engine. Noting the relative position of the rotor and module alignment marks, make a second mark on the rotor to align it with the one mark on the module.
If the crankshaft was removed or rotated while the distributor was removed from the engine, perform the following:
- Remove the No. 1 spark plug from the left-hand cylinder head.
- Position one of your thumbs or fingers over the spark plug hole.
- Have an assistant rotate the crankshaft in a clockwise direction until you feel air pressure escaping from the spark plug hole. It may take several rotations of the crankshaft to be certain of the feeling; if not sure, keep rotating the crankshaft until you are certain.
- Once the air pressure is felt escaping from around your thumb or finger, continue rotating the crankshaft until the TDC mark on the damper is aligned with the 0 degree mark on the timing mark tab. At this point, the engine is positioned with cylinder No. 1 at TDC on its compression stroke.
- With a new O-ring on the distributor housing and the second mark on the rotor aligned with the mark on the module, install the distributor, taking care to align the mark on the housing with the one on the engine. It may be necessary to lift the distributor and turn the rotor slightly to align the gears and the oil pump driveshaft.
- With the respective marks aligned, install the clamp and bolt finger-tight.
- Install and secure the distributor cap.
- Connect the feed and module connectors to the distributor cap.
- Connect a timing light to the engine and plug the vacuum hose.
- Connect the ground cable to the battery.
- Start the engine and set the timing.
- Turn the engine OFF and tighten the distributor clamp bolt. Disconnect the timing light and unplug and connect the hose to the vacuum advance.