Later style lamp Assembly Upgrade
I changed out my indicator, brake and sidelights to the later style plug in type last weekend in an effort to clean up some wiring issues I was having. The lights require a larger opening and I found that a Greenlee 1-3/4" Radio Chassis Punch works a treat. To line up the punch I took one of the old lights and snipped a notch into it, then spun it with a sharpie giving me a circle about the same size as the punch. Then its just a matter of lining up the punch with your mark.