Yes. Not in my Morgan but in my Rover-v8-engined MGB. Partially cured it by re-routing the fuel lines away from the rocker covers and by wrapping the fuel lines to the two SU carbs in reflective insulating material. You can get it online and it's self-adhesive. I suspect even the high octane E5 fuel is more volatile these days. If the vapourisation is in the carbs it may be possible to help matters with some kind of heat shielding around the float chambers. Of course modern fuel injected cars have a fuel return system which keeps the fuel circulating back to the tank so it has no time (in theory) to vaporise.
