Fred, they are not cross over at the moment, I imagine someone would use these as a basis for a new exhaust system, it would require some fabrication work to turn it into a crossover set. But it would save many hours fabricating up the primary pipes. the existing pipes would have to be welded to a new exhaust flange (to suit your engine) and then the pipes would have to be extended to go around the back of the cylinder heads where they would cross over and go into the collectors, and on to the silencer.