In Theory:
Header wraps are designed to keep the heat in the header which reduces radiant heat around the engine bay.
There is a slight, if any, performance gain.
Header manufactures or even custom header makers will void any warranty claims if header wrap is installed.
Facts:
Insulating the header with any type wrap will increase the surface temperature to molten levels causing metal fatigue and the tubing to crack. It will also trap moisture and a quick way to destroy mild steel headers.
Conclusion:
Heat wraps can be used on starters, fuel lines, or wiring in the engine bay.
Below:
These headers are destroyed after applying heat wrap within two months time. The tubing nearly crystallized
preventing any welding repair. All the tubing would need replacement.
