cause of all lights going dim ?

[Hank70SS]

Ground to fender handles everything except starter and ignition. The main ground cable from battery to engine handles those 2. AutoZone sells an electronic voltage regulator, direct replacement for the old mechanical one. They use to sell a Wells VR715 now it's sold with Duralast brand name, not sure of the new number but they can look it up.

I would start with checking your ground connections, battery connections then positive feed. Positive feed is from battery to starter. There is a main splice near the starter where positive splits off to feed the rest of the car.