My question is do the Dougs avoid the steering?
http://www.forabodiesonly.com/mopar/showthread.php?t=22379
Yes, they go above it, both sides.
The best advice on the subject so far is to buy them raw, install them and make sure the clearances work; then set up a deal with an after market coating company like Q.C. Coatings, NitroPlate, or locally (Jet-hot is hit or miss) to have them coated inside
and out. The cost is about the same if you were to buy the coated ones, but the quality is far, far better. Use stainless steel fasteners because the warranty doesn't cover rust drips.
Amazon.com has a good deal on the Doug's; as does Autozone with the %20 discount.
Good Luck, have fun!
I'd like to add this into the mix as well:
http://www.centuryperformance.com/exhaust-header-heat-wraps-do-not-use.html
and
From:
http://www.turbobuick.com/forums/threads/inside-header-coating.376780/
We've been Ceramic Coating pipes for close to 15 years. The easy answer to your question is that it comes down to the type of Ceramic Coating being used and the size and condition of the pipes being coated. First off, when most people refer to Ceramic Coating or Jet Hot they are usually referring to the “bright Ceramic Coating”. Unfortunately there is NO bright Ceramic Coating on the market that is capable of withstanding actual turbo temps for any period of time without dulling and eventually going into failure mode due to excessive temps. Unlike many other coaters, Jet Hot included, we rarely recommend bright for any street of heavily raced turbo application outside of some motorcycles, vehicles running alcohol or limited race applications because its GOING TO FAIL. Even under those circumstances the bright coating will eventually dull and or delaminate. We recommend one of the high temp Ceramic Coating offerings that is good for nearly 2000F. This material can actually be red hot on turbine housing and retain its color.
RMAR brings up a good point. The biggest issue is being able to properly prepare the ID surface of headers and pipes to accept the Ceramic Coating. Many of the coaters that tell you they are coating the ID of pipes are either outright lying or being deceitful, especially when it comes to bright ceramic as an internal thermal barrier. What they do is spray the inside of your collectors and primary tubes and tell you they’ve coated the inside of your pipes. This is BS. Not to mention, if the ID of the pipe isn’t properly prepared the material will never stick. Hence the reason Jet Hot doesn’t recommend it, because they know the way they are coating the ID is an illusion. Further, when the bright ceramic breaks off it is very hard like a big piece of chrome. At which point can damage your turbine. Again, the high temp Ceramic Coatings will not harm a turbo even if they were to fail.
That being said there are methods to prep the ID with combinations of acids and blasting if the pipes are big enough, short enough, etc to be accessed by blasting equipment to ensure that the pipes are profiled properly. Below is the aftermath of a Jet Hot coated turbo header after a short time on the dyno. After the bright ceramic dulls, it turns to a white / green and then it’s all over. It becomes sacrificial and flakes off at high turbo temps. The other pics are some similar apps with the correct coatings on both turbine houseings and turbo headers.
Hope this help…..