Source for nuts and bolts hardware

I am trying to find a source for various nut/bolt hardware for my 71 Dart project. I am looking for things like the studs that attach to the fender/quarter panel extensions, trans crossmember bolts/nuts and leaf spring bolts/nuts. I know about AMK Products, but they seem to only deal with interior fastener kits and components. I saw a supplier at the Minnesota Mopars in the Park show a couple of years back and grabbed one of their business cards, but do you think I can find it now?
I am also looking for the engine block to engine mount plates for a 340 with biscuit mounts. I can find swap kits, but mine was originally a 318 and I understand that the drivers side is different for a 340. Thanks in advance!

Jim