The volume of the cylinder is given by $V = \pi r^2 h$: $396 = \frac{22}{7} \times 3^2 \times h \Rightarrow h = \frac{396 \times 7}{22 \times 9} = 7$ cm. The curved surface area is $CSA = 2\pi rh = 2 \times \frac{22}{7} \times 3 \times 7 = 301.5$ cm².