General Motors has a new – and all-too-rare – hit. But far from solving the embattled carmaker’s problems, the popularity of the 2010 Chevrolet Camaro muscle car highlights the dilemma confronting the Detroit manufacturers over their vehicle development plans.

GM has so far taken 18,000 firm orders for the Camaro, enough to justify adding a Saturday shift over the summer at the Oshawa, Ontario, plant where the car is built.