Distributor Rotation: The distributor almost always rotates clockwise when viewed from the top (looking down into the engine bay).
Firing Order: The standard firing order for a small-block Chevy 305 is 1-8-4-3-6-5-7-2.
Wire Configuration: This is where it gets a bit tricky because there isn't a single, universally applicable diagram. The wires are connected to the distributor cap in a sequence that matches the firing order. However, the physical location of the wires in the cap can vary slightly between manufacturers.
To determine the correct wire configuration for YOUR specific engine:
1. Find the number 1 cylinder: This is usually marked on the engine block or can be determined by checking the engine's front timing cover. Cylinder 1 is typically the front-most passenger side cylinder.
2. Identify the rotor position: With the engine at top dead center (TDC) on the number 1 cylinder compression stroke, note the position of the distributor rotor. This indicates which spark plug wire connects to the number 1 cylinder.
3. Follow the firing order: Once you know where the #1 wire goes, follow the firing order (1-8-4-3-6-5-7-2) to connect the remaining wires.
Important Notes:
* Consult a repair manual: A Haynes or Chilton repair manual specific to your 1987 vehicle (make and model) will have a detailed wiring diagram and distributor cap layout. This is the most reliable source of information.
* Marking the wires: Before disconnecting any wires, use a marker or label to clearly identify each wire's original position. This will greatly simplify reassembly.
* Distributor cap orientation: Make sure the distributor cap is correctly aligned on the distributor. It should only fit one way.
* Electronic ignition: Remember that the 1987 305 likely uses an electronic ignition system, not points. Miswiring can damage the ignition module.
Without knowing the specific vehicle, providing a precise wire diagram is impossible. Use the steps above and a repair manual for accurate wiring.
