smc

The original slope and $y$-intercept are $\frac{2}{3}$ and $4$, so the new ones are $\frac{1}{3}$ and $8$ respectively. Thus, using the slope-intercept form ($y=mx+c$), the new equation is $y=\frac{1}{3}x+8$, which is $\boxed{y=\frac{1}{3}x+8}$.