I have just taken delivery of my 2006 C-6.I have had several different sports cars over the past few years but after driving a friends 2003 C-5 Z06 I realized how far Chevrolet has taken the Corvette.When the C-6 came out I just fell in love with the new the body style and seeing the stock HP go to 400 and the lateral G go to .98 (close enough to my buddies 03 Z-06) was all I needed to get me to trade in my Mini Cooper S for my new ride.I have gone over the car and am so impressed with the engineering and quality of the materials used.As a hobby I race and build open wheel formula cars so I have a real interest in the engineering behind the Corvette.I have one issue: Why is the stock exhaust manifold untreated steel.I mean this is a 45K vehicle that Chevrolet can be totally proud of.How do you as a maufacturer not at least High Temp paint it,Jet Hot coat it or something.Everyone I have looked at and these were all pre-delivery new vehicles in the showroom or on the dealers lot was already rusting including mine.I like to keep my cars pretty stock but I got the feeling that manifold will be refinished or replaced shortly.Anybody have any ideas why they leave them unfinished other than to save a couple of bucks.... or have I answered my own question.

 

cast-iron is as cast-iron does. Put as set of SS headers on it if you are going to go to the trouble of swapping them out.

 

 

The exhaust manifolds aren't steel. They are cast iron. All small block Chevys since 1955 have used unpainted cast iron exhaust manifolds. While cast iron will develop a light coat of surface rust, it won't rust through the way steel would, ie it will hold up for at least several hundred thousand miles while steel would be gone in 20,000 miles. So there is no engineering reason to paint the exhaust manifolds.

 

Some C5's has stainless steel manifolds, the double-wall stuff. To keep mechanical noise down, GM uses double-wall stuff OR Cast iron.

I can't speak for 06', but my 05' has (nearly) polished heat shields over the manifolds, and you have to really look hard to actually see the ugly, cast stuff.

 

Well I feel better knowning they are cast iron but Engineering issues aside the sight of rust (even if its just on the surface)is annoying on a car of this caliber.I guess I know why so many go with headers on the cars.Anyhow, I love the car and really apprciate those who responded to my inquiry.

 

It's very rare that an exhausts maniford is replaced due to rust. If they get overheated they warp and crack but even that is rare.