Leave the cap on the distributor, and you'll see that same spark at every terminal. I used to use an old Sun distributor tester as a drive unit, and spin up a HEI distributor in it, then put one plug wire on it and hold the spark plug in my hand, being careful NOT to touch the machine. The plug would fire every time the rotor came to that terminal- - - - -it gave me a little tingle, but the students were amazed that I could hold onto it! The other seven terminals would fire a long spark back to the coil laminations.
Jerry
