new headlights

Do not use higher wattage lamps with the existing wiring. It was barely adequate when new, and the additional strain of more current flowing trough the wiring and switch could cause a meltdown or worse a fire. At a minimum you should add a headlight relay and power the new lights directly from the battery. Someone posted a link in a different thread yesterday showing how to do this.

Also, the original alternator was probably only 35amp. Anytime you start adding additional electrical loads (lighting, audio gear, fuel pumps, fans, water pumps, etc) you need to access the power requirements vs what your charging system can support.