I'm going to be putting a new set of headers on my big-block Duster. They are the Pro-Parts design stepped headers made by TTI. They will be replacing an older set of Pro-Parts design non-stepped headers. On the previous set I wrapped the headers. Over time they frayed and looked like crap. I like the look of coated headers and take this street/strip car to the occasional show. But I imagine coated headers don't do as good of a job with containing the heat. What's the experience of you guys?

100% coated.

I've never been a fan of header wrap. I hate the way it looks and, in my experience, it deteriorates the headers themselves.

Stainless

I coated my stainless headers to control under hood heat.
So you can probably figure where I come in on the debate.

Me too, all the time

I love the way coated headers look, but im always amazed at how the wrap all but eliminates any heat from the exhaust. I do some work in the natural gas industry, and the natural gas engines I work on have the entire exhaust wrapped. Natural gas engines exhaust is a lot hotter than your run of the mill hot street car and race car running off any kind of gas.

Just as an example, these engines are governed to run at 1500 rpm, 80% of the run time is "loaded", but the rpm stays the same. The manifolds glow red, and if you bump your hand into the wrapped portion of exhaust, you feel pretty much nothing.

Not to hijack, but what about those exhaust jackets?

The problem with the wrap, it exceeds the reliable heat range of the exhaust material, which leads to rapid oxidation ( view as rust) and metal fatigue, as the metal excessively expands and contracts thru every heat cycle. You can wrap SS and not have same downsides to a point, or wrap CI or Inconel, but mild steel will not last. My guess on the constant speed motors, they are not mild steel tube manifolds..

I'd love to have gone stainless, but my only option on these headers was mild steel. But I did get a stainless-steel price, lol.

The coated headers I've had in the past seem to run as hot as non-coated headers. On my last set of headers, I painted them, then wrapped them. Didn't get any rust (but I do live in southern CA). I might just do that again and just deal with the ugliness

Ive heard, don’t know for sure, that coated inside and out frees up HP, same with the wrap. And something about stainless is better than mild steel for HP

Header wrap on mine, it works great, its time to redo them after 9 years, the wrap has gotten crunchy & from having to pull the headers a few times it is time, where it has come off the headers still have the black paint I put on them, no rust at all. they have over 11k miles on them the 2nd pic is when I first did them

Engine builder Jon Kaase says that engines with uncoated mild steel headers and a cam much bigger than stock will vacuum the rust out of the headers into the engine.

So even if you choose to wrap the headers I would get a good coating that will last.

He says when they take an engine apart he can tell if it had uncoated mild steel headers or stainless headers.

Millions of rusty engines

If you look at the TTI books they offer Ceramic Coated, Ceramic Coated with thermal barrier on the inside, polished and black ceramic. NOBODY orders just the plain ceramic and most opt for the Ceramic with thermal barrier. It gives the cleaner look while also reducing heat under hood. The heat stays in the pipe and if you remember you high school science class the hotter the gas, the faster it flows. So if you are coating go for the inside and out. Interesting concept about the rust being sucked back in the engine, but I am sure he found evidence of it.
Todd

Probably so...

my manifolds and mild steel piping for the turbo setup on my Fury have been wrapped for 9 years now and I took it apart over the winter and all the pipes are just fine. Street car that is never driven in bad weather. I had wrapped headers on my coronet for years and it sat for long period in a shop that 'sweated' as the seasons changed and those headers were also fine. I'm not sure how severe of treatment is necessary for wrap to cause premature fatigue on pipes but I think I've tested past most people's use cases.