Auto body repair & detailing: Bace coat clear coat, grease remover, tail lamps

Question
My friend wants me to paint his 64 1/2 Mustang which he purchased in a restored condition.(Nice) It presently is Purple which he wants to change to Black. I recommended base coat clear coat. I have painted a few things(Vans, Airplanes, motorcycles) but I am not a professional. My question- do we need to remove all existing paint or can we scuff then base coat clear coat? He lives in Wisc. and I live in Virginia. He was going to trailer it to me for a long weekend to paint. Stripping the existing paint would take to long for his planned trip. Should we go another route?
Thanks
Paul

Answer
If the paint is intact, with no cracking or checking, it's fine to paint over the old paint. Let me point out, however, that unless your friend has the car completely dismantled, there is no way you can paint it over a long weekend. By dismantled, I mean all door handles and interior pieces, emblems, bumpers and grille, tail lamps, and anything else that may get in the way. The vehicle will need to be cleaned with wax and grease remover prior to any sanding to remove wax and armor all. Do it twice, the entire car. Painting an entire car is a lot of prep work, especially if you are doing an overall color change. It's easiest to paint the jambs, and then paint the belly of the lids with the lids off the car. Flop the lids over, leave them on some saw horses, and paint the car. This will allow  you to paint the engine compartment, and you will get less trash in the lids if they are painted off the car. Bill