i have an 04 lb7 stock injectors my cp3 hung up ripping the teeth of the wheel also my cam gear crank gear was good still. getting into it more blew head gaskets and no compression to the cylinder on either side sooo leads me to the motor build pulled motor taring down injectors are really dirty sending heads off to be resurfaced and injectors to be cleaned tested and honed 30. my question is on the injectors if they test bad then do i change just nozzles or whole injectors ?? im new to the diesel world and its probably a stupid question but not to familiar with the injectors?? opinons excepted thanks