This is the cylinder numbering. On the drivers side nearest the radiater its 2,4,6,8... And on the passenger side nearest the radiater its 1,3,5,7.... Also you can look on the intake manifold port runners to each cylinder and find that cylinder number cast into the aluminum. then on the passenger side of the intake air horn you will find the cylinder fireing order. Now not all number one injecter lines are the same demension. there is a differance between the truck and the vans. If your number one injecter line has that odd looking fitting just under the line nut then you have the truck hard line. If its not there but its found on the number 4 hard line then you have the van hard lines on a truck.. Still not a problem because they work fine that way... Just don't try to force fit the wrong line on a truck or van by stretching the line to make up the missing fitting. That will never work.
