That is the special timing fitting found on many 7.3 engines. It was used to time when the original Ford timing meter was used. Some still have the protective plastic cover on them too. They are the same size as the hard line nut so be sure to use a backup wrench under the fitting so the injector does not loosen up when you remove it... Be especially sure to re install it or all your timing will be way off. There is a way to remove this fitting but.. you need the hard line from the van engines because they do not have this fitting on the number one cylinder like our truck engines have.. On the vans this fitting is found on the number 4 cylinder. No matter what you do the original line length must be kept the same.
Note about cylinder arrangement. All cylinders on the drivers side are even and on the passenger side they are odd numbered. From the radiator back they are numbered 1,3,5,7 on passenger and 2,4,6,8 on the drivers side.
