Strange problem...

[classic]

Howdy all - It's been awhile! I am experiencing a strange or odd occurance with my '65 Malibu. I believe it to be electrical and maybe someone else has had this same problem.... I am running a DUI 50,000 volt HEI distributor and coil with a Summit CD Ignition Box for starters. So, I have noticed that after the car is running awhile and warmed up, maybe a half hour+ I start to notice an electrical noise like a buzz that fluccuates with the RPM. At idle you can hardly notice it but the higher the RPM the more distinct the buzz becomes. The strange thing is this... periodically the car will just shut down just like you reached down and turned the key off. No popping or running ruff, just dies. It happened to me yesterday and I coasted over to the center lane put it in park and it started right back up again and I had no other issues the rest of the way home. I am first think the coil but wondering if it could be the ignition box making the electrical noise and shutting down. Anybody else ever have a problem similar to this? I would appreciate any ideas or feedback.
Thanks,
Greg