Know I've looked at this info several times before, but I'll be damned if I can find the thread where belt length is covered. All I could find was a blog about length where someone says the common lengths range between 1400mm and 1420. I just removed a 1439mm Napa part (25-060560) and it was fine with no idler pulley. I've decided I want to run the idler now and need a longer belt. Anyone know what I need or can send me the link to the correct thread?