This procedure addresses a common misunderstanding: the 1966 Corvette 327 V8 uses a distributor ignition system and does not have a camshaft position sensor. This guide explains the distributor-based timing system for reference.

Warnings

Tools required

Preparation

1. Ensure engine is cool to the touch
2. Park vehicle on level ground and engage parking brake
3. Open hood and secure with hood prop
4. Locate the distributor at the rear of the engine block, driven by the camshaft through the distributor gear

Procedure

1. 1

   Locate and inspect distributor
   The distributor is located at the rear of the intake manifold, in the valley between the cylinder banks at the back of the engine. It is driven directly by the camshaft via a helical gear and serves the function of camshaft position sensing in this mechanical ignition system. Visually inspect the distributor cap for cracks, carbon tracking, or corrosion.
2. 2

   Remove distributor cap
   Release the two spring-loaded distributor cap clips by pressing down and rotating them 90 degrees, or remove the two screws securing the cap depending on your distributor type. Lift the cap straight up, keeping spark plug wires attached. Inspect the inside of the cap for carbon tracking, burned terminals, or excessive wear.
3. 3

   Inspect rotor
   Remove the rotor by pulling it straight up off the distributor shaft. Inspect the rotor contact for burning or excessive wear. The rotor transfers spark from the coil to the distributor cap terminals as the camshaft rotates the distributor shaft. Replace if damaged.
4. 4

   Inspect distributor shaft and advance mechanism
   With the rotor removed, visually inspect the centrifugal advance weights beneath (if accessible) and check for excessive play in the distributor shaft by attempting to move it side-to-side. Minimal play (less than 0.020 inches) is acceptable. Excessive play indicates worn distributor bushings and requires distributor rebuild or replacement.
5. 5

   Check point gap or pickup coil (if applicable)
   If equipped with points ignition, inspect the points for pitting or burning. Point gap should be approximately 0.019 inches (new points), with dwell set to 28-32 degrees as the controlling specification. If equipped with an aftermarket electronic ignition conversion, inspect the magnetic pickup or optical sensor for damage or debris. The condition of these components directly affects ignition timing accuracy.
6. 6

   Verify distributor gear engagement
   The distributor is driven by the camshaft through a helical gear at the base of the distributor shaft. While you cannot see this gear without removing the distributor, listen for abnormal noise from the distributor area when cranking the engine. Grinding or clicking sounds indicate potential gear wear.
7. 7

   Check vacuum advance operation
   Locate the vacuum advance canister on the side of the distributor. With engine off, disconnect the vacuum hose and apply vacuum using a hand vacuum pump or by mouth suction. The breaker plate inside the distributor should move visibly. If it does not move or fails to hold vacuum, the vacuum advance diaphragm is ruptured and requires replacement.
8. 8

   Reinstall rotor and cap
   Install the rotor onto the distributor shaft, ensuring it seats fully onto the shaft. The rotor has a square and round locating hole to prevent incorrect installation. Reinstall the distributor cap and secure with clips or screws. Ensure all spark plug wire terminals are fully seated in the cap.
9. 9

   Verify ignition timing with timing light
   Connect a timing light to the number one spark plug wire. Start the engine and allow it to reach operating temperature. Aim the timing light at the timing tab on the front cover and harmonic balancer. Initial timing should be set according to specifications for your specific 327 engine code (commonly around 4-12 degrees BTDC depending on horsepower variant — verify against the factory specification for your engine). Adjust timing by loosening the distributor hold-down bolt and rotating the distributor body as needed.

Reassembly

1. Ensure distributor cap is securely fastened and all spark plug wires are properly routed
2. Verify vacuum advance hose is reconnected if it was removed
3. Double-check that no tools or rags were left in the engine compartment

Verification

• Start the engine and listen for smooth idle with no misfiring
• Verify ignition timing is within specification using a timing light
• Test drive the vehicle to confirm normal acceleration and no hesitation under load
• Monitor for any ignition-related issues such as backfiring or hard starting

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