There are two inductive pickup leads on most Sun testers- - - - -a chrome-plated one that clamps over the coil wire and a red one that senses a signal from the #1 spark plug wire. Which one do you need? The coil wire lead can also accept an inductive probe that clips over the coil in the distributor cap on a GM HEI distributor. The same basic inductive probe as the #1 plug sensor is used on Sun timing lights.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!