Hi All,
As Steve indicated, there have been many discussions on how to cool our Healeys during a HOT Summer and this has been an area of past discussion, as Steve has indicated, due to the high recent costs and scarcity of a Sleeved thermostat. Although I have a sleeved thermostat in my Healey to eliminate this issue, many in hotter climates have eliminated the thermostat altogether and just installed the sleeve to aid cooling. If you drive in a temperate or cooler climate, this may not be the best idea and combining the sleeve with a standard thermostat will take some modification (additional flange space) to allow both (thermostat/sleeve) to fit properly and tight under the hose bowl. Although this has not been a difficult task, its issues have been addressed in past threads and should be reviewed before attempting.
Keep Cool (not necessary to say with the coming COLD Vortex),
Ray(64BJ8P1)