The distributor cap and rotor can only fit one way onto the distributor. If the distributor remained in the engine, there is no problem. If you remove the distributor from the engine and do not mark its position, then you crank the engine until #1 piston is at Top Dead Center, then install the the distributor.

Now notice on the TOP (not the side) of the distributor cap the is a “1” raised letter. That indicates the tower where No 1 spark plug wire goes. Knowing the firing order, you can now plug in all your wires.

The firing order on a SBC 350 V8 is…1-8-4-3-6-5-7-2. If you are planning to replace your ignition wires always do 1 wire at a time. The # 1 spark plug is the drivers side front of the engine. Trace that ignition wire to the distributor cap and you now have #1.

The white powdery stuff is oxidation from the high voltage arcing the gap from the rotor to each post. The spark normally jumps at least an 1/8″ gap inside the cap.

For you to get rid of corrosion, you should clean the distributor cap with wd40.

Drying The Cap

1. Place the cap upside down, and spray it with your carburetor cleaner.
2. Shake the cap around gently, to allow the cleaner to reach every crevice.
3. Use a clean, lint-free, dry towel to dry the cap out completely. Leave in a warm place for an hour to complete the drying process.

What’s happening is that the moisture that’s stuck inside the distributor cap is compromising your spark. The spark is sufficient when all the other conditions are perfect, but once rain or moist air steal additional energy via the old spark plug wires, the engine starts misfiring.

There is a drain hole in the floor of the distributor housing, There will be water come in around the base of the distributor cap, Or the Adapter if you do the upgrade. A little weather strip adhesive will help keep the water from FLOODING into the distributor.