I have 70 454 4 spd and recently bought a KHE-300 radio and new speakers. When playing the Ipod, it sounds great all the time. The FM sounds great when idling but has a popping/crackling noise when I am driving.

To my knowledge, there are no longer any noise suppresors left that came on the car. Is this what I need or what else can I do?

 

The BB engines came with grounding wire mesh around the spark plug wires and radio noise filters (capacitors) on all switches and rotating parts (blower, alt.) to limit 'pops' and 'whine' from the radio signal. You should "test" all of your accessories, etc. with the radio operating to see which ones present the problem: with engine "OFF" work all of the on/off switches in the car and the brake pedal to see which ones put clicks/pops into the radio output; those will need a capacitor/filter on their circuits. Then start the engine and, as you lightly rev it, listen for any buzzing/whine in the radio output. If you have some, disconnect the alternator connector to see if the noise goes away (or reduces). If so, you will need one on the alternator too. If the noise went away completely when you removed the alt connector, you will not need any filtering/shielding on the engine; otherwise, you will need to add shielding around ignition components and/or around the spark plug wires to eliminate all noise in the system.

In a way, the noise you are hearing is a bit surprising. Most modern radios have employed methods to limit RF noise from entering their devices. You might want to run a direct line from the radio ground to the battery ground line (you must also disconnect any existing ground line you have in place) to see if that will solve the problem more easily.

 

Still have the distributor shielding?