10 is the normal limit. You could have a big pin 10 mil that rubs, you might have someone say they have a 11 or 12mm motor custom made that doesn't need it.
The two 14 mils I've seen around here, one being a cub...the other a cheetah, were both epoxied.
There was a guy selling the aluminum plugs to go in the honeycomb on the bottom of the cases to weld in, my buddy tried to get a set, not got back to him....
If it's a 14 in stock cases, there should be a little build up of some type behind the cylinders on the cases, and...if you really want to look underneath it, welds or epoxy as well..