I remember my dad and uncle used them on their cars WAY back in the day because most cars had steel fuel lines, a mechanical fuel pump and 94 octane pump gas, so they used cool cans to help stop vapor lock. As for today unless you're running an old school setup, most use return style regulators, so you wouldn't need a cool can because the fuel does not sit in the line and get hot vapor locking. Not sure if they still do or not, but I seem to remember seeing them on quite a few NHRA stock/super stock cars. However, if they still are using cool cans in those classes, its probably for contingency money. I've seen them on the cars, but never see the person putting ice in it between rounds.

Now for me, I did run a cool can on my '69 Z/28 "427" back in '84-'86 because when I moved to Arizona it was much HOTTER than Ohio, but I switched from using ice to using dry ice and alcohol. I can tell you that when I made the switch to dry ice it DID make a difference. Then I found a path to a new NOS Cheater nitrous plate system. LOL.

Wes