Engine Noise through stereo

I didn't catch the nature of the engine noise you're experiencing. If it is a whine or a howl, it is being generated by the alternator. If it is a ticking noise, it is coming from the ignition system. I think the ignition issues are being covered well.

Back in the day, guys used to put choke coils on the antenna leads to get rid of the whine. I had alternator problem with the 73. Digging around my junk (as my ex- used to call it), I came up with a biggie about the size of a frozen OJ can. I plugged it in and ended the problem. I'd tell you more about it if I could but there are no identifying marks or labels on it. It looks like a silver OJ can with a short antenna lead coming out of one end and an antenna lead socket on the other.