FBO's black HEI ignition box

...And plug gaps:
[1] 'The bigger the gap, the more energy the first & most critical nanoseconds of the spark has.' D. Vizard

[2] 'Use as much spark plug gap as possible for a strong running but not to the point of misfire. With most race ign systems the plug gap tends to be in the 050-060 range'. D. Vizard