I have a popping sound coming over the speakers of my 67 coupe. The pops are directly tied to the engine rpms. What do I need to do?

 

This is a very basic system. No amp, no subs. Just a head unit and 4 speakers. No power windows, locks, or seats either.

 

start with a better ground for radio

 

^ agreed, sounds like a bad ground or ground loop.

 

alternator noise is the term for this, and as they said it often comes down to a ground problem. It can be at the radio or a engine/battery ground problem.

 

On a separate thread, I was asking about a loose wire up near the alternator. I think we have determined it is a ground wire. This may solve the problem!

 

your alt should be grounded through its chassis, there should be no ground wire going it other then for the voltage regulator inside maybe....

 

From my wiring diagram, there shows a ground "spliced into one of the leads between the alternator and the regulator.
The wire that is loose matches this diagram.
I'm not sure if this is the source of my popping or not, or even if it is the ground shown in the diagram, but could it be my issue if it is?

 

Looks like you found your problem. Trace it back to make sure it matches your schematic.