Need some parts locating help

I sold my 76 Martinique to a friend a couple years ago who no has some problems. he took the boat to a hack of a mechanic to have a new control box installed. The hack took off the old box and all cable mounting hardware. He has a new box (does,'t look like the right one to me) and no cable brackets (throttle or tranny). Where can I find a source to either find some diagrams for part numbers or a supplier who has a parts guy who is older than 19 and knows these boats? Looks like every other PCM/Velvetdrive setup I have seen or owned, but no help form the local suppliers. Any and all help is greatly appreciated. Doug