Some resistance in the # 1 (exciter) line is enough to stop the run on.

A diode is one way to create the resistance, an 'ignition' resister is another.

And a bulb, which is basically a glass jar containing a piece of high resistance wire that heats up so much it glows, is another.

'51 Chevy 1/2 ton w/'62 261, HEI, offy, fentons, dual carter/webbers, t-5 & 12 bolt posi