Something to think about. What the other people said is true about the car just using what current it needs, BUT, if you have problems anywhere in the wiring like corroded connections and so forth that big alt is just going to feed what ever the bad spots need to get what they want, which leads to overheating and a fire possibility. Let me give an example. I have a 75 model motorcycle that the contacts inside of the ignition switch were pitted or corroded or something bad, cause when I gut to a high enough RPM it would draw so much current that the solder joints on the back side of the switch would melt and the wire would fall off. Just a thought.