Sorry for the long wait! My email notification has disappeared for some reason... As you already know each tooth is 18 degrees, so it could be off alot in either direction. The factory turbo gear times the cam in at about 111, which is 4 advanced. I find the adj gears to be off, so I'd try to match it up to a stocker first to see where "0" is, & yes the hole should be straight up compared to the head, but the cam has to be ahead of that reference slightly to be "stock"... I hope this helps......
Hybrid booster
Garrett booster