I have a '71 340 Challenger w/drum brakes on all four corners, the brake drums are orange. I have heard that this is correct & I have heard it is not correct. Does anyone know for sure what the correct color should be?

What wheels did your car come with? The plain steel wheels in most cases are bare, road wheels are the ones I believe they got the red treatment. I don't know about rallye wheels, think they a;so got the red treatment.
I'm sure someone who knows 4 sure will chime in.

Brake Drum Paint - RestoRick

Looks like that would be the stuff. Thank you. Just for the record, it came with road wheels.

The factory assembly line book

Wow! That's great, thank you. Have a great weekend.

I believe most non-steelie wheel cars either had orange or red paint only on the face of the drum thats visible through the rim. I also believe red was used more frequently on earlier car and orange started later in 70 and up. Steelies had no paint.