When is a genuine Shelby no longer a Shelby

[Thor maine]

I asked this question in another thread, CSX 3016 Syosset for sale. My question is when is a real genuine Shelby Cobra from the 60's , no longer and becomes something else? Ok so you have a real genuine CSX from the 60's and it has a long race history. So as a racer it no longer has the original engine as is the nature of racing you change and destroy engines. And say because it has so much race history that it has little or no original body and add in a few big crashes and you replaces the main frame rail and because you were there you replaced the other with a higher quality main tubing and most of the suspension with higher quality components. As Carroll Shelby said "AC used a lot of pot metal". Very little of the genuine car is left, is it still a real genuine CSX from the 60's. If not what is it and if it is does all the race history add to its value???