<<<recommended some internal coatings but I don't recall
> if he did the exhaust. >>>

I coated ALL internal engine parts that touch exhaust heat.

Piston tops, combustion chamber, exhaust port, exhaust valve face and radius,
intake face, exhaust pipes from head to muffler.  I wrapped the muffler in a
heat wrap (I was not sure how I would like the mufflers sound and the straps
would damage the coatings).

There are several reasons for coating:

1) To put a barrier between the aluminum head surface and the rubber head
gasket to prevent the corrosion process from starting.
2) To protect the engine from any increase in heat with the added power.
3) To reduce the temps that the rubber head gaskets operate and increase the
life
4) To reduce the temps that the other rubber and electrical engine
compartment components operate.
5) To reduce or eliminate the cracking of the head between the valves, that
lead to leaks and other problems

I was not looking to do this for a power gain but to protect the expensive
parts, any extra power is a benefit.

The company I choose was Swain-Tech coatings.   www.swaintech.com

All my coatings cost me @$600.  When I was looking at ways to protect the
head surface, I thought about coating the head surface.  I decided to coat
the head and then, thought that the coating might cause the piston to run
hotter, so I decided to coat the piston top as well, then I thought about the
exhaust valve running hotter, so I coated that, then the port will be hotter,
so coat that, then the exhaust pipes will be hotter so coat that.

So you can see one change to the engine affects other parts so the entire,
You need to consider all the ramifications of a change to the stock engine,
so any part that would be made weaker by changing one part can be made
stronger.

Robert