I hear people say keep it original, and though I understand the logic and respect the opinion, IF you are going to keep it and don't care what the resell value it - my rule is - have fun with it the best way you can.
I bought the '77 S & S and it was in bad body shape - and WHITE... my least favorite color. I had just got the green '92 and loved the color... so, I whilst doing body work I changed the '77 from white to green, and it quickly became one of my favorites.
You can pretty well bet that the value may drop on a car if you deviate from originality, but I don't care what it does to the value. If I like the car and want it my way, why should I stay with a color or design just in an effort to stay original?
I say this with a tremendous amount of respect to the previous posters who offer a differing opinion.
My vote: if you want to make an ambulance out of of it, go ahead... the only downside to me is idiots who would holler "ghostbusters!" at it then...
(though a straight hearse, I offer my color change photos below)