I have just discovered that National (owners BP-Shell dropped the Benzole bit) were responsible for the introduction of SMURFS to Britain as part of a marketing campaign. The little devils were given away at filling station.
Its all coming back to me now, and so will the nightmares.
Here's one of the first advertisements from one of my transport books to promote the new-name new-style National petrol.
Cleveland Discol - I'm used to think my engine ran cooler, the car went a bit faster !! It was more interesting buying petrol in those days - all that so- called 'choice' compared to buying today. I'm trying to remember about having my tank filled by a forecourt attendant, but I can't - it would certainly slow down things at Tesco's etc.
I had a half share in a Colortune many years ago,they seemed to worl really well. I seen to remember one removved a spark plug, replaced it with the colortune and it acted like a plug but allowed you to see the ingition "flame" and one adjusted the mixture control until the flame was a certain colour.
This was easy on the superior S.U. carbs and I dont really think it went out of tune to any degree but it allowed one to tamper with the engine!!!