contact a local newholland/ford tractor dealer. and see if you can get a copy of a page or 2 of the owners manual, that shows belt routing. and the pulleys and twists within the belt.
pending on mower deck, you might need to contact manufacture of mower deck to get info.
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tossing it out there...no idea if it would help....
newholand.com goto agriculture -> parts ((takes 3 to 5 clicks to get to the online parts manual)) you might find some parts detailing pulleys.