As far As I know there is at least 1 Chevy which participates:
entry # 232 a Chevrolet Protruck driven by Eric Vigouroux (suppose that's a custombuilt car based, presumably, on a Blazer)
Currently, after stage 5, on the 33rd place 1 hr 22 minutes behind the leader (include a 1 hr time penalty)
Just check
http://www.dakar.com/2004/us/index.html
for the details of the race