318 Engine stumble

The polarity is for what the particular HEI module is designed to work with. The polarity refers to the the + or - direction of the electrical signal from the pickup. Yes, the pickup will line up exactly the same but the electrical polarity of the signal to the HEI module will be the opposite. This will make the HEI module trigger at a different rotation angle. The signal waveform is discussed in the link in post #109.

I've stated what I would do in post #118: Look at the picture with the 3 pickup coils shown side by side. Take yours out, and compare to the pix to see which you have, and then go and buy the one with the opposite wire color. LOOK at the wire colors in that pix. Or cut your pickup wires, solder them reversed, and heatshrink-protect the solder joints.

Buying another distributor is OK too.