Shorthand fan power formula constant

This is a short post to help me recall where the magic constant comes from for the shorthand fan power equation in IP units.

I’m talking about the 6343 constant in this equation below:

${\displaystyle {\stackrel{.}{W}}_{fan}\mathrm{[hp]}=\frac{\stackrel{.}{V}\mathrm{[CFM]}\Delta P\mathrm{[in\; w.g.]}}{6343{\eta }_{fan}}}$ ${\displaystyle \mathrm{CFM}·\mathrm{in\; w.g.}=>\frac{{ft}^3}{min}in·water\left(\frac{1min}{60s}\right)\left(\frac{62.427961\frac{lbf}{{ft}^3}}{1water}\right)\left(\frac{1ft}{12in}\right)\left(\frac{1hp}{550\frac{lbf·ft}{s}}\right)=hp}$