When I installed the Dual Dutra's on the slant in the 83 D150 back around 2010 I had them powder coated by Indy Powder coat. They say they used a high temperature material suitable for exhaust manifolds. However it did not take long for rust to begin showing through and of course IPC does not warranty coatings on exhaust manifolds.
A couple of years later I had the engine out and re painted the manifolds and down pipes with VHT aluminum colored aerosol spray paint. The color was a dull aluminum and although it did hold up on the exhaust manifolds in about a year it did begin to flake off the down pipes.
May of 2021 I had the engine out of the D150 to replace the clutch and also swapped in a different cam. At that time I cleaned up-stripped the exhaust manifolds and down pipes and painted them with Rustoleum High Heat Ultra aluminum. That paint dried to a very shiny silver color. The truck was driven last May to November of 2021 and from April to late July of 2022 and this paint is holding up great.
Just though I would pass this on.
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