Is it a new motor? Or has the distibutor been out? In the past when I have seen glowing headers the timing has been way late or retarded and the fuel was still burning as it left the cylinders. This can happen if you are a cylinder off on the distributor rotation. Instead of being advanced on #1 like you think, it is actually way retarded on #2. I sure hope that makes sense, I don't know how else to describe it. Double check to make sure your rotor is pointing to the #1 wire on the cap when the motor is at TDC.

Pat