tighed1,
I have the 181 pulley also. I just went out and checked it to verify the belt position. The belt is riding completely on the CP as spec'd. This is a 115.3" Gatorback belt that I put on about 6 weeks ago.
I also pulled the factory belt out of the drawer and checked it. All ribs accounted for and I ran it all summer while making track runs and regular driving.
I noted your comment about the outer ribs being taller than the rest. I got a dial caliper out and could not see or measure any difference across the factory belt or a spare Gates 115.3" belt. I did note that the factory belt is .220" thick and the Gates is .190" thick. But they are both flat all the way across.

MikeR