I got a goodyear gatorback 4081377 after searching for the right part number for my dual alternator 7.3. I thought that was it, but after i did the belt tensioner and two idler pulleys, it seems like it is a bit long. The indicator on the tensioner is all the way to the third notch. Is that correct?

 

I think your you good to go.. Here is mine, only a tiny bit difference. I just changed it not to long ago and i don't have the dual alternator, but the indicator should read the same.

 

Thank you for the picture, much appreciated!

 

here is mine with the duals

 

There are two belts, one is almost 1" longer than the other one. If your unsure, take your vin to ford and they will let you know which one is the correct one.