Voltage range for points

My 68 is acting up again, and I am suspecting excessive voltage. I was getting 14.7-14.8 V at around 1500 rpm yesterday. Later, I was at 14.4. Power windows etc seemed to move faster than usual. I think this may be excessive, and may be frying the points. Any knowledge of what the maximum voltage should be? I thought around 14V is about right.

Thanks