Ok here is my issue!
I have a 1985 prospect ram truck.
it has 20,000 original miles that is documented.
this truck is in mint shape other then the exhaust.
From sitting the muffler is in bad shape and I have removed it a couple hours before this post.
when I start this truck and let it sit while running at the end of the manifold (I believe the resonator) turns cherry red in minutes!!
what would cause this?
how do I fix this?
I need some help on this guys!

thank you

 

Do you have a catalytic converter on your truck? Back then, some did and some didn't. If you do, it may be plugged or collapsed inside. If it's clear or you don't have one, then your preheat valve may be stuck. This is on the passenger side exhaust manifold and has a round weight on it. These rust in place. What they do is divert exhaust gasses through the intake to warm the engine up faster and run better in cold weather. With the engine cold, you should be able to reach down and move it. There used to be repair kits available but I've always just taken it out. The last one I did was years ago but I think I pulled the manifold off, removed it completely and brazed the holes shut. I've also seen the cross over passages plugged up with exhaust residue. I'd check the valve first..

 

Yep, and I'd also ask what motor? V8 or I6?