Complete tune-up for 1966 Corvette 327ci V8 including spark plugs, points, condenser, distributor cap, rotor, ignition wires, fuel filter, air filter, PCV valve, and timing/carburetor adjustment.

Warnings

Tools required

Parts

• Spark plugs AC 44 or equivalent × 8 — AC R44 or equivalent 14mm tapered seat
• Distributor point set × 1 — Delco D-100P or equivalent
• Condenser × 1 — Delco CS-153 or equivalent
• Distributor cap × 1 — Delco D-204 or equivalent
• Rotor × 1 — Delco D-308 or equivalent
• Ignition wire set × 1 — 8mm suppression wire set
• Fuel filter (inline) × 1 — 1/4 inch inline filter
• Air filter element × 1 — Round 14 inch diameter element
• PCV valve × 1 — Delco CV-780C or equivalent
• Valve cover gasket set × 1 — Cork or rubber composite

Preparation

1. Park vehicle on level surface and engage parking brake
2. Allow engine to cool completely (minimum 2 hours if recently run)
3. Disconnect negative battery cable
4. Remove engine air cleaner assembly by loosening wing nut and disconnecting breather hoses
5. Label all spark plug wires with cylinder numbers before removal to ensure correct reinstallation
6. Gather all parts and tools before beginning work

Procedure

1. 1

   Remove old spark plugs
   Starting with cylinder #1, remove each spark plug wire by twisting the boot (not pulling on the wire) and pulling straight off. Use compressed air to blow debris away from spark plug wells. Remove all 8 spark plugs using the spark plug socket and ratchet. Inspect each plug for fouling, oil deposits, or abnormal wear patterns which may indicate engine issues. Keep plugs in order if diagnosis is needed.
2. 2

   Inspect and gap new spark plugs
   Verify all 8 new spark plugs are correct type for the 327 V8 (AC R44 or equivalent, 14mm tapered seat). Check and adjust gap to 0.035 inches using feeler gauge. Apply a thin coat of anti-seize compound to the threads of each spark plug, avoiding the electrode area.
3. 3

   Install new spark plugs
   Hand-thread each spark plug carefully into the cast iron cylinder head to avoid cross-threading. Once finger-tight, torque each plug in sequence (cylinders 1 through 8) to specification using the torque wrench.
   Torque spec

   Spark Plugs — Cast Iron Head30 Nm (22 lb-ft)
4. 4

   Remove distributor cap and inspect
   Label each spark plug wire position on the distributor cap if not already done. Remove the distributor cap by releasing the two spring clips or removing the two screws. Inspect the old cap for cracks, carbon tracking, corroded terminals, or burn marks. Inspect rotor for burning or excessive wear on the contact point.
5. 5

   Remove and replace ignition points and condenser
   Note the position of the rotor for reassembly reference. Remove the rotor by pulling straight up. Disconnect the primary wire and condenser wire from the point set terminal. Remove the point set hold-down screw and lift out the old points. Remove the condenser mounting screw and remove the condenser. Install new condenser and tighten mounting screw securely. Install new point set with hold-down screw loosely in place. Apply a small amount of distributor cam lubricant to the distributor cam lobes.
6. 6

   Gap distributor points
   Rotate engine by hand using a wrench on the harmonic balancer bolt until the rubbing block of the points is on the high point of one of the distributor cam lobes. Loosen the point set hold-down screw slightly. Insert a 0.019 inch feeler gauge between the point contacts. Adjust the points by moving the adjustable contact until the feeler gauge has slight drag when pulled through. Tighten the hold-down screw and recheck gap. Reconnect the primary wire and condenser wire to the point terminal.
7. 7

   Install new rotor and distributor cap
   Install the new rotor onto the distributor shaft, aligning the square and round locating holes. Press down firmly until seated. Install the new distributor cap, ensuring it seats fully, and secure with spring clips or screws. Transfer spark plug wires one at a time from old cap to new cap, maintaining correct firing order: 1-8-4-3-6-5-7-2 (clockwise rotation).
8. 8

   Install new spark plug wires
   If installing a complete new wire set, route wires from distributor cap to each spark plug in the correct firing order (1-8-4-3-6-5-7-2). Cylinder #1 is front driver side. Number cylinders 1-3-5-7 on driver side (front to rear) and 2-4-6-8 on passenger side (front to rear). Ensure wires are routed away from exhaust manifolds and moving components. Press boots firmly onto spark plugs and distributor cap terminals until they click into place. Use wire looms or clips to secure wires.
9. 9

   Replace PCV valve
   Locate the PCV valve in the driver side valve cover. Pull the old PCV valve out of the grommet in the valve cover. Install the new PCV valve by pressing it firmly into the grommet. Reconnect the PCV hose to the valve, ensuring a secure connection to the carburetor base or intake manifold.
10. 10

    Replace fuel filter
    Locate the inline fuel filter between the fuel pump and carburetor (typically at the carburetor inlet). Place rags under the filter to catch fuel spillage. Using two wrenches, loosen the fuel line fittings on both sides of the filter. Remove the old filter and note the direction of flow arrow. Install the new filter with the arrow pointing toward the carburetor. Hand-tighten fittings, then snug with wrenches. Do not overtighten brass fittings.
    ⚠Gasoline will spill when disconnecting fuel lines. Have rags ready and ensure adequate ventilation. No smoking or open flames.
11. 11

    Replace air filter
    Install the new air filter element into the air cleaner housing, ensuring it seats properly on the bottom rim. Reinstall the air cleaner assembly onto the carburetor, aligning the mounting stud. Reconnect any breather hoses to the valve covers. Secure with the wing nut, tightening hand-tight only.
12. 12

    Reconnect battery and initial start
    Reconnect the negative battery cable. Turn the ignition key to ON position (do not start) for 10 seconds to allow fuel pump to prime the system. Check for fuel leaks at the new fuel filter. Start the engine and allow it to warm up to normal operating temperature. Engine may run rough initially until timing and carburetor are adjusted.
13. 13

    Set dwell angle
    With engine at normal operating temperature and idling, connect the dwell meter according to manufacturer's instructions. Check dwell reading on the meter. Specification for V8 with points is 28-32 degrees. If adjustment is needed, stop engine, remove distributor cap, and adjust point gap (wider gap decreases dwell, narrower gap increases dwell). Recheck after adjustment.
14. 14

    Set ignition timing
    Locate the timing mark on the harmonic balancer and timing tab on the timing cover. Clean marks with wire brush if necessary. Connect timing light to cylinder #1 spark plug wire according to timing light instructions. Disconnect and plug the vacuum advance hose at the distributor. Start engine and aim timing light at timing marks. Loosen the distributor hold-down clamp bolt. Rotate distributor body slowly until timing mark aligns with 4 degrees BTDC (or specification on emission decal if present). Tighten distributor hold-down clamp and recheck timing. Reconnect vacuum advance hose.
15. 15

    Adjust idle speed and mixture
    With engine at normal operating temperature, adjust idle speed screw on carburetor to achieve 600-650 RPM in neutral (manual) or drive (automatic with wheels chocked). Adjust idle mixture screws by turning them in gently until engine begins to stumble, then back out 1.5 turns as a baseline. Fine-tune each mixture screw for smoothest idle and highest vacuum reading. Final idle mixture screws should be approximately 1 to 2 turns out from lightly seated. Readjust idle speed if necessary after mixture adjustment.

Reassembly

1. Perform final visual inspection of all connections, ensuring spark plug wires are fully seated
2. Verify all tools have been removed from engine compartment
3. Check that air cleaner assembly is properly secured
4. Confirm no fuel leaks are present at fuel filter

Verification

• Engine should start easily and idle smoothly between 600-650 RPM
• No misfires or rough running should be present at idle or under acceleration
• Timing light verification should show stable timing mark at specified setting
• Dwell meter should read steady 28-32 degrees
• All spark plug wire boots should be fully seated with no arcing visible in darkness
• No fuel leaks should be present after several minutes of running
• Test drive vehicle to verify smooth acceleration and no hesitation under load

More procedures for this vehicle