[N0DIH]

HEI's had issues with the rotor burning through to the first thing they could arc to, the weights/springs. They took a hit. First sign that something is up is the rust color there. Keep the plugs/wires/cap and rotor in top shape, when the wires and plugs are weak, all the HV has to go somewhere, and the rotor takes the brunt of it. They should always be inspected closely.

WD-40 doesn't last too long, I would recommend some white lithium grease on the pins for the weights. They do wear, and will get oblong causing timing to get more erratic.

Glad you brought it up Justin, the HEI is an awesome distributor, and well maintained, will be a solid performer for almost any car, street or race!

Always inspect closely the cap and rotor wear. The rotor for burn through, and the cap for the HV arc to be stuck in one spot, that is a sign the mechanical or vacuum advance is not functioning properly. Always check the index of the cap too, if the HV arc is to one end of the cap contact, and never moves, (ECM cars are far more suceptable to this), and it is starting to arc off the end of the contact, the cap may need to be indexed. I did a post on how to in the Cad 4.9L/4.5L/4.1L section sometime back. It really improved the idle/low rpm drivability in my 85 Cutlass Olds 350 (was a 307) and the CCC computer system.

I have a "trick" good HEI mod (uses only factory GM parts) that really helps the starting and idle/off idle drivability in the HEI for high compression cars. If anyone is interested, let me know. It really works well with a non ECM HEI. Low compression cars it can help as well.