My take on customized autos from the 1930's to 1960's cars. No one I know would customize one of these without a great deal of thought to the value. For example: a stock 1966 Chevelle with a 396 motor is going to be worth a lot more if it was ordered with that motor, if it still the original block, and if all of the components of the car are correct as produced. I.E a stock factory Super Sport is worth a bunch more than a modified one with the wrong engine and so forth. A clone or, frankencar if you will, has nowhere near the value of the original, even when all of the components are combined into a tasteful package. In auto collecting, like watch collecting, orignal condition, is everything.
Are there exceptions to this? Maybe, but they are few and usually involve a celebrity.