I dirt track race and mine did it once it was because it was running to lean.
Normally a blocked catalytic converter or a blocked exhaust will cause that problem. Back pressure, means the gasses cannot escape. thus causing the manifolds to glow.
The engine runs fast, won't idle down, and many times the exhaust manifolds will glow red hot from the lean mixture.
Plugged converter possibly or other exhaust restriction. exhaust is very very hot, because of this, your exaust manifolds/headers are going to get very very hot, especially if you tend to run high RPMs. if everything else like throttle response is fine, i wouldn't worry
Advanced timing can cause that to happen
Exhaust manifolds get very hot, it is possible but not a common occurance
The exhaust gasses pass though there, and they're really hot.
When the driver let's off the gas pedal going into a turn raw fuel gets pumped into the exhaust manifold. The manifold is so hot the fuel ignites and you see flames from the exhaust pipe. It's totally normal.
Inlet manifolds are actually called intake manifold and this is to allow air to be injected into the fuel for either a rich or lean mixture for either performance or gas mileage (which can be adjusted). The Exhaust manifold is used to expel your burnt fuel, or air/fuel mixture, during the exhaust stroke on a 4-cycle engine to allow room for the intake stroke to bring in your fuel, or air/fuel mixture. The exhaust manifold simply directs the exhaust and become extremely hot. The exhaust is pushed out by the exhaust stroke.
The exhaust manifolds on a normal, properly tuned vehicle engine WILL NOT overheat to the point they glow unless you have a turbo setup. If this happens you have improper fuel mixture or the timing is off. Even a turbo setup should only have a small bit of orange glow and that's only if you're running the engine hard. This will help you: http://www.hotrodders.com/forum/rebuilt-350-headers-get-bright-orange-170314.html
The fuel mixtue has gone lean.
Exhaust is overheating the starter, starter may be going bad or exhaust could be starting to plug up and getting to hot near manifolds
exhust valve and guid sufficiant ply./exhust valve improper set/advance iginition timing.also locked muffler.fuel,gas, tomuch high flow. ahmed mirza neduet