Ok my stock 1967 Mustang has a 289 4v and c4 trans. Over the past few years I have maintained it very good and replaced things as needed. I have one consistant problem that just recently got worse. When my can is running at idle, the dash and head lights dim and brighten to where they look like they are blinking. The alternator needle also bounces. They dont go totally off, just dim and brighten. When I acellerate, it stops. When just driving less than about 45-50 mph, it still happens, just not as obvious. Its almost to the point when I's stopped at a traffic light at night it looks like my lights are blinking. Any ideas? Over the past year I have relpaced the alternator, voltage regulator, solonoid, and the alternator wiring harness.

 

I had the same problem with my 66. I saw the fix in Mustang Monthly. I replaced my voltage regulator with a new electronic one. It solved the problem completely. The old ones have a spring and moving parts that cause the flickering, the electronic one has no moving parts. I didn't do it but I'm told if you want to keep the stock look you can remove the cover from your old one and put it on the electronic one. Mine was $15 from my local auto parts store.

 

Well your advise was correct. I grabbed an electronic voltage regulator ($45) from a local parts store and it seems to have corrected the problem. Thanks.