Keke Rosberg used to smoke on the grid up to the last moment so he had a bit of nicotine in his blood for the start. Several times I thought he wouldn't be able to get his helmet on in time...
Nowadays F1 is far too physical for a smoker to have any chance whatever of being competitive. It changed with Schumacher who was able to keep up qualifying pace lap after lap, no driver could do that before, everybody has to be able to now.
My only knowledge of NASCAR goes back to a time as a consultant in CART. One of the crew chiefs worked in both series and what he told me about NASCAR was basically that it was not a level playing field, to say the least.
I got to know Bill France, now long dead, when we used to do Goodyear tyre tests at Daytona road track in the early 80s. Keke and I were invited onto his boat for a barbeque and all the other guests were track managers of his circuits (plus his sons). Great stories, particularly Bill's, some of which were a bit "blue" for the blue-rinse wives of the track managers
My favourite was on guy who told a story about Bill being unhappy about the spread out field at one race and told the race director to hang out the yellow flag. "why sir there is no reason?" "well what about debris on the track?" "there isn't any sir" Bill takes of gold Rolex and chucks it over the wall "there is now"