Slow Blinkers need help!

So I'm not the best with electrical and need some pointers here.
I have a all original 69 dart, still original wiring. I had to replace the alternator when my battery died and since my blinkers have been blinking very very slowly, when i come to a red light or stand still they dont blink at all. Not until my rpms go up and the alternator cranks out more juice. I just replaced the voltage regulator last week thinking it would fix the problem (i didnt change it when i replaced the alternator) it helped a little but now its back to the same old problems. Is this common? Should I replace the blinker fuse thingy too?
Any input will help, thanks guys!

-TheOriginalDart