I'm more than familiar with coatings..
as you can see here..
http://www.aircooledtechnology.com/coatings.htm
And here
http://www.aircooledtechnology.com/coatings_2.htm
Coatings help with some things, but they won't solve design and material flaws. I have seen huge results with certain coatings, and some detrimental effects of others. I am doing a ton of R&D on coatings as we speak and when I geta good grasp on what each one does look for a huge article on my site.
The bottom link there illustrates what DLC coated parts look like. DLC is "diamond like carbon coating" and to do the parts you see pictured there cost 1100.00, as you cen see getting data does not come cheap.
I Have seen benefits of ceramic coated valves and chambers but they won't keep your heads from leaking and won't effect engine temperatures enough to overcome the evil of the big huge "Cast iron clunkers" that are better as boat anchors than cylinders.