I use these. Gets pretty hot where I am so cooling is always an issue. There is two types, thermo contact and thermo resistor..you want this type, contact, resistor is for guages. They simply bolt onto the head/block and are rated about 82/85..thermostat temp. The part number is on the box. You can be really smart and use a lazer temp gauge to find the hottest spot..but I just bolt em on the head somewhere so they touch the jacket...