Need Help With This One! 1966 Mustang

Hello everyone! So I'll make this short n sweet. I bought a basket case and I'm not giving up on this one. So with that said I need help with where to buy bolts and nuts that did go with this 1966 coup? Also was a straight six and came with a 302 with some sort of serpetine belt set up. Dose not work! So I need to buy a kit, anyone know who sales a good one? A/c p/s alt w/p full system! oh and how can I tell if the wire harness was for an a/c car? I'm quite handy but never messed with a stang. I've been working on this car for over a year and have learned that this poor car was some sort Frankenstein project from who knows how many owners! Hints why I don't know what bolts and nuts go where! If I could get a full bolt,nuts,screws, kit for the entire car that would be awesome lol

Thanks for the reply! I'll have to take a pick of the wire harness so u guys can see what I'm looking at. It just dose not make sense because every thing I have wired in ecept this bundle of like six wires that runs over to the passenger side! Some wires leads have been cut so ur guess is as good as mine. I'll take a pic today.

P.s. I did find the heater wires to the heating element and blower motor wires so it's none of them! Oh and glove box light and under dash lights are wired already. My guess was for an a/c unit for under dash!