I have heard about thermal barrier coatings for intake valves, piston tops, heads, etc. that reduce the heat transfer to the incoming air charge for a cooler/denser air charge. Anyone have any experience with these coatings?

yes. i ran them extensively in their " hey day" and considered them a waste of time and money. all my motors were normally aspirated. some other builders that dealt with turbo motors running very edgy compression and boost levels claimed it helped them make things live at extreme limit... but i never saw any of that. there is a place for these thermal barriers and coatings but it is my opinion that in 95 % of what we would consider nominal conditions, they fall into the " magic bean" sector of seperating you from your money with no measureable , repeatable or discernable real world benefit.

Thanks for the information. I will not waist my time or money on this.

I second that!

I did the pistons,cylinder heads and valves on my blown 540,I have it out of the boat to freshen it but haven't had time to tear it down to see if it did much or not yet,in a few months I'll post with pics and my experience,Smitty

The point of doing the thermal heat barrier coating that I am aware of is to get more HP because the incoming air picks up less heat as it passes by the coated intake valves, pistons and cylinder heads and less of the combustion energy (HP) is robbed by being absorbed as heat by the piston combustion chamber and exhaust valve. Is there another reason for the thermal barrier coating?

less friction=hp as you already know but if the engine oil is doing its job the coating shouldn't make a difference in that aspect.The main reason I coated my pistons was to try to keep the skirts from scuffing when running sustained boost on the edge of a safe afr. My last 2 motors the pistons looked ok but had burn't oil on the bottom side of the piston crown and slight scuffing on the skirts (I'm thinking from the excess heat),I would assume from getting fairly hot under boost. I will report soon if these look any difference when I tear it down,Smitty