[jhein]

Originally Posted by steve25

Do not just unplug the wires from the plugs!

You need to kill the power to the HEI other wise when cranking the motor it’s still producing a spark with no where to ground out to so then it can arc across it’s coil and harm that.

This is the same issue that can take place with any system with a coil, even a points system.

Thanks for that. I would have probably done that anyway because just because it's so easy and it would be the safest way to proceed. But, it's good to know there's a sound rationale for it as well.