Well, let's see.
Nascar, they can travel as fast as they want.
Corvettes are street driven, and must drive the speed limit. Regardless of what their top speed MIGHT be.
So, in a practical sense, a Nascar vehicle wins hands down.
And that's because you didn't specify at all, what kind of race it is. Drag race? Nascar race? Drift? Autocross? Each would have it's own abilities in each one.
And since you failed to do that, I have to assume you mean, fastest, in every day use. A Nascar vehicle, in everyday use, is 150+mph. A Vette? Under 70mph. Nascar wins.
Which is more comfortable? The Vette.