Not to bad, I am 90% through an I6 to V8 conversion and just replaced the I6 fuel line from the tank to the engine bay with a V8 line from the tank to the engine bay. You will need to purchase replacement clips, since the majority of them are one time use only. The clips are a bit of a PITA to get out if I recall, and to install them, just use a pair of pliers and squeeze the butterfly together. I did disconnect my rear brake line, the flex section and made it a lot easier to manuever the removal and replacement line in that area. In addition, don't forget, you will need a new section or rubber fuel line, about 3" or so, that goes from the tank to the line........the old one may be the origional. Mine was pretty dry rotted, surprisesed it did not leak. I went with stainless steel as a replacement which may be overkill since the car never sees weather anymore. As for the pre-bent lines, they are 99% correct ot all the contours, my replacement V8 line was not as snug in a section you will not have to worry about with the I6 line replacement. If you are like me, doing it in your garage with no lift, a lot of work on your back an car on jacks. You will say a few choice words during removal/install, but very doable.