[davidimurray]

If they are glowing red at idle then it's not really a problem - you can't do much damage at idle. If it is glowing red above this then it is running lean - or - you have an air leak in the exhaust. Often people discount the air leak theory but I've seen it quite a few times. The most dramatic being while running an engine on a dyno - one guy was mapping, I was running the dyno and another was lookout. We had the engine at 12000rpm tuning the top end of the map, everything looked good -exhaust gas temps near the headers were good. Suddenly there was a loud bang everything got very loud and my underwear changed colour. On getting everything turned off and getting in the dyno cell it soon became obvious that we had a problem - only half the silencer remained and that was glowing bright red! Turned out that with all the vibration the silencer had worked loose and was sucking as much air as it liked through the joint. The resulting burning inferno inside the can melted it!