hello i have a 74 350 and installed a cam and gears and broke in the cam
during break in at 2500 rpm # 8 cyl the hedder was glowing red but not on the others can anyone tell me what would be causing it.
thanks for any info kev

If it's just the one cylinder, check your valve adjustments and then check for obstructions in the intake port. Your running lean in that cylinder.

Glowing exhaust means a retarded and/or rich mixture.

incomplete fuel burn is completing the burn in the exhaust pipe, thus making the header glow.

Bigger cams require a richer mixture at idle due to more valve overlap. So you can't do much about that. Therefore, all you can do is advance the ignition timing. You may need to reduce the overall timng curve (recurve) and advance the timing to 20 degrees at idle. 20 inital which advances to 38 total works in most situations.