Glowing Headers
You say that you noticed that the headers were glowing red in the morning, does that mean that they were red after it was started and warmed up at idle or after it was run on the highway or around town.
You state that the timing is "right" because your friend just set it. What did he set it to? Does it still have the vacuum advance and where is it receiving vacuum from? Did he set the timing with the vacuum advance hose removed?
Every time I've seen red hot headers from an idle speed warmup it's been caused by retarded timing.