They don't look like anything I've ever seen on a factory 350...
That being said, it appears they bolt to the outer valve cover bolt locations. the outer two holes would be for the wires, the center bit is just a divider. Most every factory set-up I've see have the wires coming off the cap, around the back of the VC's, down and in behind the exhaust manifolds, then come up to the spark plugs. The set you got look like they're meant to be routed over top of the VC's...which was definitely not ever how it was from the factory.