Flickering lights

Car sat in shop for about 12 years before I decided to get it running. I don't recall having this degree of light flickering (it's really bad) when I sat it up. The alternator has been replaced with a different one than it had when sat up, and the voltage regulator also. I did the MAD Electrical amp gauge bypass, and followed the instructions to a Tee. It has also had a new headlight switch and dimmer switch installed. Any ideas?