It depends what type of Corvette vs. what type of Porsche. Certain Corvettes are faster than certain Porsches and vice versa.
porshe
The new ZR1 Corvette is the faster.
Stock the Ford GT is faster then a standard Corvette, but not faster then the stock corvette Z06
corvette
a corvette is faster than a Hornet
Corvette ZR1
corvette
A 2006 350Z is faster than a 2006 manual Porsche boxster, but is not faster than a 2006 manual Porsche boxster s.
Porsche
The Porsche Carrera GT is faster. There are lots of sites where you can find that out.
Koenigsegg but a Porsche is more reliable
2011 Corvette