uneven exhaust temps
 

I have a 2000 7.4mpi with EMI manifolds and the starboard side manifold runs consistently 30 degrees hotter than the port side. The water hoses feeding the manifolds have the same heat variation, port side cool, starboard side much hotter. Is this a normal variation or cause for concern? The engine block and head temps are even both sides.

I am a fan of the crossover system, some here say they are not nessesary. I use the system with the bypass hose and thermostat with (2) 1/8" holes drilled in them. My temps never fluctiate and both sides of the exhaust are always the same. The only other thing I can think of would be a restriction somewhere. Maybe sand or debris?