What is this thing ???

it is a type of electronic ignition. used a lot on lawn mowers, chain saws and even some cars too. most common along with the others is a motor cycle. capacitive discharge is what it uses to discharge current output to fire the spark plugs.

mostly that's what wiki said. someone else might know more about it.

is it something you just found laying around?

No , it was mounted on the latest 63 Valiant I bought , I replaced it with the HEI system( coil and mount from a 97 GM truck ) .

Steve

ah that makes sense, that can be found on cars sometimes also. good that you replaced though i think. it has a short charging time and sometimes isn't enough to make reliable ignition. good to hear you got hei on your car thats definately nice to have