On turbo engines I have ceramic coated the inside and outside of the headers, heat coated tops of pistons and combustion chambers, and anti friction coated piston skirts. Guy I knew did it as a sideline and did it for me at cost.
Seemed to work well... for the month or so the car was together.
It deadhooked and twisted the chassis, and i parted it out.
Ohhhhhhhh the fun of being young, stupid and impulsive.
Its much nicer to be older, stupid, and impulsive
Jim