I recently bought an 82 Z28 that they removed the stock 305 and put in a newer 350 with a 700r4 trans. My gauges have been acting really strange. Lights in the cluster will randomly come on and blink along with the blinkers. So I bought and installed a new gauge cluster and it does the same thing.

I've heard it may be a ground, but I don't know where to start checking or even how to. Any tips??

 

Having the same issue, when my turn signal is turned on my blinker goes slow and the TACH bounces with the turning light, also affects my fuel guage, oil guage, Happened when I removed the cluster to put in a new speedo cable. Hate driving around with it all apart!