And about to get much longer...
M'Lud, in the history of Motorsport (always capitalised), there have been many cases of cars with a significant history or value being questioned as to the originality of their components. Some, indeed, appearing to have only the air in their tires as original.
However, Harrumph, it is unquestionable that in some cases, but unquestionably not all, that despite many, and possibly most, of the mechanical components being replaced in the day to day maintenance of a highly stressed mechanical contraption such as a racing car the original entity remains and continues as said entity.
In support of said statement we give you (And you are welcome to it M'lud) the story of Bentley "Old Number One"-and God save all who sail in her...
The Case of the Bentley Old Number One
When questioning the integrity of "experts" from England it is always wise to remember this case, M'lud, since it influenced the outcome, attitude and wherewhithal of so many fine dealers, collectors, fettlers and punters in that fair land.
Harrumph!