Fingers crossed. Turns out burned out side markers affect the rate of turn signal blink. They worked great on 4 way flash, which shares a signal flasher with the signals themselves. This fuse box is still 60's style glass fuses. all the other f bodies I’ve seen had a more modern setup. With the 4 way on everything worked as it should at a normal blink rate, but the signals themselves would go once in five to eight seconds.
Things got a little quicker when I shortened up some corroded grounds and soldered new ring terminals etc, but it was cleaning up some corrosion on the rear side markers and replacing the bulbs got everything blinking properly. Funny thing is the side markers are only that. They come on with the parklights and do not blink, but do share a ground wire with the single ground wire right where the trunk latches. So it makes sense in that it’s basically always the ground, but doesn’t make sense that it would effect the blink rate as they are closer to the ground (path of least resistance and whatnot).
Even if I don’t know the scientific explanation, (fire made it good) I realigned the electron mojo whick replenished the elusive blinker fluid.
Here’s a picture of the same car in 1981.