Charles Hunt wrote:70s Gunson (IIRC) colourtune was a plastic bodied spark plug. You were looking for a blue flame, not that over-rich orange and red!!
Ah, memories. I still have mine lurking somewhere. (And they're still available!)
“I am somehow less interested in the weight and convolutions of Einstein’s brain than in the near certainty that people of equal talent have lived and died in cotton fields and sweatshops.” Stephen Jay Gould