Originally Posted by Lonnie Pavtis

An overly rich mixture will not be hotter.... rich mixtures will burn slower & often burn into the exhaust causing glowing headers. This directly relates to the retarded timing issue as a rich mixture will require more advance to prevent this.

Fact is, that as you lean the car (from say 12:1) it will cause a hotter burn as the mixture leans out towards stoich. Deping on the actual engine configuration, peak temps are somewhere in the mid14:1 range. Go leaner & it will then start to cause an additional drop in temp as well.

This is why most cars stay at 13:1 or richer to prevent engine damage under full throttle. Thats why they say lean is mean. It will generally run the best on the verge of damage.

Get an EGT & wideband, the results are very factual.

Originally Posted by SS RRR

i think what some of you are missing is the fact he observed his headers glow slightly in the dark. i highly doubt there's any kind of problem.

Originally Posted by 97bowtie

This isn't necessarily true. My car ran terribly when my crank reference angle was off and the headers would glow bright red in the dark, but you couldn't see any glowing during the day.

Originally Posted by mobleman

Noted, but as I mentioned, in my case it was a very dull glow.. not bright at all.

Great info from all on this thread!