1. Ensure that the engine is at Top Dead Center (TDC) on the compression stroke for cylinder number one. This can be checked by aligning the timing mark on the crankshaft pulley with the pointer on the timing cover.
2. Remove the distributor cap and rotor.
3. Locate the distributor drive gear in the engine block. It is usually located at the front of the engine, just below the water pump.
4. Align the distributor drive gear with the camshaft gear. The distributor drive gear has a slot that must fit over the camshaft gear's tang.
5. Place the distributor body into the engine block. Ensure that the distributor body is seated correctly in the block and that the drive gear is engaged with the camshaft gear.
6. Rotate the distributor body until the rotor points to the number one spark plug wire terminal on the distributor cap.
7. Install the distributor cap and rotor.
8. Connect the spark plug wires to the distributor cap in the correct firing order. The firing order for a Chevrolet 305 engine is 1-8-4-3-6-5-7-2.
9. Start the engine and check the ignition timing. The ignition timing should be set to 0 degrees before Top Dead Center (BTDC).
