Exhaust manifold inner surface treatment

[Christian]

I used to know of a company that offers to treat the inner surface of your existing cast iron manifold with the purpose of speeding the gas flow thus helping the gas and the heat to get out of the engine. Unfortunately, I lost the brochure and forgot the name.
Would anyone know of such a service / company?

 

[Vettehead Mikey]

I'm quite sure the words 'snake' and 'oil' would be part of their name. What's wrong with good old porting and polishing?

 

[73shark]

Were they using a process called Extrude Honing?

Jet Hot ceramic coating is the way I went. Looks almost like fresh cast iron, is smooth, and really reduces the heat under the hood.