If it is a car that has the trip tag on the cowl, which spells out the code for the original color(s) of the car, and you paint it a different color, it will have a negative impact on the future value of the car. It's your car, so you can do what you want with it. If you have to change the color, if you stick to a correct color that was available in that model year, you will lessen the negative impact. In other words, painting a 50's or 60's car with modern pearl white would be totally incorrect, and although it might look great, it would not be period correct at all.
If you are planning to keep the car for a long time, make it the may you want it.
Brian