Could an 'oversized' alternator cause problems? i.e. I would like to install a 180 amp alternator in my 65 El Camino. Will this cause problems?

No, you alternator will only put out what your electrical system demands. Now this is true with a stock electrical system and factory accessories only. If you are installing stereo components that draw lots of current, then you want to make sure the alternator output is sufficient to supply all the electical needs of your car, including lights and A/C.

No. You will need to run a much heavier wire from the alternator to the battery. Also, make sure you add extra protection for the stock wiring system. A short causing 180A to be pumped through the stock wiring can cause big problems (car fire :( ).

Peter