\[\left( 5\frac{1}{3} \right)^{7} \cdot \left( \frac{3}{16} \right)^{8} = \left( \frac{16}{3} \right)^{7} \cdot \left( \frac{3}{16} \right)^{8} =\]
\[= \frac{16^{7} \cdot 3^{8}}{3^{7} \cdot 16^{8}} = \frac{3}{16}.\]