Hello everybody; first post! I recently replaced my alternator with a high amp aftermarket alternator and while I was under the car I noticed that the lower mounting bracket holding the alternator in; the bolt with the square head going through that bracket and the lower portion of the alternator is missing the nut on the other end. I've tried a couple generic metric nuts from Advance, but I couldn't get the right size. In addition, with the alternator I have in currently, I need a smaller belt in order to get the proper tension- probably an inch or so smaller. Anyway, rather than going to my local dealer, and probably not getting a straight answer without paying copious amounts, I've come here to ask the community. So I'd like to know, what is the size of that nut that I need, and what is the size of the STOCK alternator belt?

Edit: Stock belt size is 4 rib 30.5", alternator pivot bolt nut is 14mm