hi john, the return lines are on the bottom of the injectors,and they connect to each other from opposite sides. i.e. number 6 connects to number 5 from the left side of number 6 to the left side of number 5. number 5 connects to number 4 from the right side of number 5 to the right side of number 4, and so on. (i think). is there a difference from early to later ones? i have been told that the early ones have the injector lines laying flat and the later ones are standing up. also, this tractor came out of canada and it has the control rod and the pivot linkage still on the tractor. maybe some day i will find a set of shutters for it.