Re: Oh my! I bought the Black Mamba and didn't know it!
The part number for NAPA should be K081145 and K081153.
My understanding is that with the crank pulley upgrade, some are making the tensioner very very tight and on others cars the tensioner is not changed. Mine had almost no give at all with the 185 installed, and that's why I went with the bigger belt.
Hope this helps.