Spacer fits perfectly on an M8 stud, and seems like it will be the right width with the water pump installed. That M8 hex-head bolt you see here is a temporary mount I just found in my garage; the real 150mm M8 double-ended stud (just like the original from the Pettit kit) is coming in the mail in a week or so. I had to order two, so if anyone needs an extra one it's up for grabs as I won't need a second one.