I did a lot of bench and flight testing on NACA ducts and the the one thing that showed was that even 2 degrees of positive rake showed huge gains in pressure recovery. Have them at 0 or worse, a few degrees negative and they rapidly perform much worse.
On the Moose here, we see high positive rake, so probably works fine, even with the rounded corners.
I like that it looks like a geared starter (save weight) but I'd also like to know what the ducting to the radiator looks like. It doesn't seem like if follows the aspect ratio rules to get the best cooling (to close to the inlet).
Not to dismiss the effort, but bolting an LSx x to an airframe is just not 'cutting edge' anymore. Guy took a proven motor and copied best practices. Glad it worked out.