Here are details of two companies, Zircotec and Thermo-Tec, who sell products which may be of interest to those who wish to reduce under-bonnet temperatures or thermally shield various components.
I have no personal experience of all of these high-tech products but testimonials like the Classic Aston Martin one below seem impressive.
"Most classic cars have very poor thermal management from new. Our customers today don't want to be cooked.........or have the finish of their rebuilt engine ruined by heat within a few thousand miles. They also expect reliability equivalent to modern vehicles, so components and fuel systems have to be protected from the heat of the engine. The Zircotec coating has proved extremely effective at addressing all of these issues."
http://www.zircotec.com/casestudy/class ... cars/37/11
Zircotec:
http://www.zircotec.com/page/exhaust-system-coatings/60
http://www.zircotec.com/page/heatshield_products/97
http://www.zircotec.com/page/home/1
http://www.zircotec.com/page/--performa ... te--2-/139
http://www.zircotec.com/page/endorsements/83
Thermo-Tec:
http://www.thermotec.com/