ok here is a quick question. is it normal for headers to glow red? at about 3500 rpm. i noticed while timing my truck and checking full advance that after a while the pipes right of the heads were starting to glow red. some more than others.

 

That usually means the timing is too retarded. Try advancing the timing.

 

Also could be a lean condition.....

Russ

 

Russ is right. I hadn't thought of that. How do the plugs look?

 

But don't forget that in general, even if timing and mixture are correct, thin steel headers will dissapate more heat then heavy cast iron manifolds. That is why so many headers are coated with JetHot or something similar. Ever see the dyno engines in magazines where the headers are glowing red?

 

This is true. However, those engines are hooked up to a dyno, and putting out full power, usually at much higher than 3500rpm's. All he's doing is free revving it up to 3500.

 

could the cause be to much back pressure?

 

timing is set at 12 BTDC . i decided while reving it i would close the choke a little. sure enough the engine picked up speed and the headers didn't glow anymore. but the bad part is i am using a autolite carb and no one sells new main jets . or do they? anyone know where? i need size 58 from the shop manual it says. i have 54 in there now. thanks for your help.

 

If nothing else you can drill the jets out. It would be way better than running it lean.

 

bear,

i like your thinking. but where would i find a .067 drill bit? or something that small?

 

For .067" that would be #55 drill bit, it is .067" exactly. I have used clock reamers, made notes on how far up the taper to repeat as well spare jets then road tested with fuel / air ratio gauge.
.....=o&o>.....

 

I have a numbered set, a letter set and a metric set of bits. It is amazing how close you get to what you need with that many choices, including the standarc fraction of and inch set of bits.

 

Bear 45/70, your correct on metric drills to get that "between size" holes that fractional, number or letter drills don't cover. A person can never have too many spare jets specially if your drilling and reaming as you will over do it more than once.
Gashog, if your headers are turning red you will damage even ceramic coated heads coating without external airflow.
.....=o&o>.....

 

don't worry about fancy ceramic headers here. i went with cheap dynomax 16 ga heads with 3/16'' flange. the piant is gone already.

 

The paint that is shipped on the headers is not meant to be left on. It is for rust prevention only. The instructions say to completrely remove the paint and repaint with a good high temp paint. Don't paint over it either or it will peel right off. Don't ask how I know this. LOL