If $x - y = \frac{7}{4}$ and $\frac{1}{x}-\frac{1}{y}=\frac{14}{3},$ then $ x^3 - y^3$ is equal to :

$\frac{433}{32}$ $\frac{433}{33}$ $\frac{217}{64}$ $\frac{217}{32}$

$\frac{217}{64}$