ignition resistor glowing red hot on back side?

Usually there's a thin ceramic cover over the backside to cover the element. But that's why the thing is made of ceramic, because that's what a resistor does - soaks up some of the voltage, thereby lowering the voltage to the coil, and converts it to heat. Measure the voltage to the coil with a VOM and see what it is - I believe the resistor drops it to like 9 volts. Any issues - replace the resistor.