OK... so I took the thing out of the shroud using a gear puller and compared it to my OEM unit.
It looks like I'm missing some spacers but no sign of anything on the Pelican website about this as an add-on part. Maybe they didn't send me all the parts? Take a look at the image and you'll see what's wrong here.
Anyone with experience with this I'd love to hear what you used to put proper spacing in there. I'm thinking this would be a very fine tolerance or I'm going to ruin the alternator bearings/etc if only slightly out of spec.
-Kale