mcannon I would use bees wax on the exhaust after it was warmed, or a produced exhaust "dressing", but not a "paint-type" product. The porosity of cast iron would allow for a decent painted finish only if there was never a drastic temperature change.
I am going to attempt to season my exhaust like a Lodge cast iron skillet this time. That's the best example I can think of.
I already gave the "high heat" paint companies their chance. That stuff just makes a lot of choking smoke happen when it's burning off. How hot does the Stovebolt exhaust manifold get??? Dayum hot.
Calyx is the brand (I think?) of produced manifold dressing most often used. I think folks here have had some great results with it. It is easy touch-up from what I hear.
I will post my exhaust coating experiment here in the coming weeks.
calyx manifold dressing (exhaust and intake manifolds)
It has to be easily "redressed" every year or two. This is very easily done with a toothbrush, with the manifold in-place
It is not quite so quick-and-easy. I did the "first coat" on a manifold/set off the engine, after media-blasting the manifold/set (just the exhaust manifold, or, both manifolds). You do not have to have bare metal (off the truck). You should, however, removed all grease and flakey-metal from the manifold.
I have used Jett Hot ceramic coating on three exhaust manifolds with great success. You send it to them and they blast it and coat it. It's pricey but sure looks great and lasts.
~ Phillip 1949 GMC Suburban - 10 year project 1952 Pontiac Chieftain Convertible straight 8 hydramatic 1945 GMC half ton truck - Driver- Sold 9-15-25 1946 Chevy COE - SOLD 1-5-26 BUH BYE CHEVY! 1959 GMC Half ton long bed NAPCO
Figure around $350 with round trip shipping. This includes the manifold, the exhaust collar and the thick round factory washers that hold the manifold to the cylinder head. Well worth the expense if you ask me if your looking a manifold that looks perfect and the coating will last a long time. I know a few other old truck members with the same Jett Hot coated manifolds that are in the 10 year and 20k mile range and they still look new.
~ Phillip 1949 GMC Suburban - 10 year project 1952 Pontiac Chieftain Convertible straight 8 hydramatic 1945 GMC half ton truck - Driver- Sold 9-15-25 1946 Chevy COE - SOLD 1-5-26 BUH BYE CHEVY! 1959 GMC Half ton long bed NAPCO
