It'll fit. Or you make it fit. Simple.
This post sponsored by Dremel - making cases fit coolers one bit at a time.
Or....if you haven't got the 140 Power version, could use the 140 Rev A which at 165mm has lots of air space. Check with Doyll, but the performance between the two is close enough for air shoes or fan darts. Or closer.
Usually case suppliers err on the side of caution with hard limits. They don't tend to state 170mm MAXIMUM when the real max. is 169.5mm.
This is in stark contrast to fan marketing mavens. Can be assured their 120mm fan physical dimensions are accurate - however performance numbers are....open to imaginative speculation. There's so few customers with calibrated SPL meters and air flow measuring gear, so larger than life numbers are rarely contested. However, accurate height measurement devices are plentiful and inflationary dimensional claims are easily verified.
So...I wouldn't worry and buy a Dremel.