If the car is running with 12 volts, you may want to buy new headlights. New bulbs on 12 volts are plenty bright. Before you put in new headlamps, clean up the contacts that they fit onto to make sure you are getting a good clean connection, and you aren't losing any power to a dirty connection.
Headlights not working
decode vin 1973 Volkswagen beetle
1973 standard and super beetle
10w30 same as a 73 standard beetle
approx. $1,400
trailer
how do replace an accellerator cable on a 1973 bug
How I have to do for replace a little bulb on the ODO speedometer cable on 1973 Super Beetle ?
You can fit quite a few. Here's the web address for one: http://www.partsgeek.com/catalog/1973/volkswagen/beetle/carburetion/carburetor.html
http://www.newbeetle.org/forums/showthread.php?t=23784 Yes, they can.
1600 cc.
12 volts