I honestly don't even know where to begin. Three years ago, my mother, in her infinite wisdom, bought an 01 LS from a shady Hispanic gent with 150ish thousand on the odometer. 3.9 liter, as you can expect. Problems came to bare it's teeth immediately. O2 sensors went bad, replaced them, car overheated and spat out antifreeze. Fixed that, (and I should add, and you all are gonna cringe, she ran 87 octane every single time. Not once 91 or up.) and kept on driving. Next the car overheated two more times, managing to somehow keep the block from cracking. Then the all too infamous timing chain tensioners failing. Now, instead of being smart, she kept driving it. I'm talking, "Hey, let's get on the highway and floor it," driving. She parked it nine months ago, and said it's mine if I piece it together. I tore the front of the engine apart, replaced both tensioners on both sides, as well as replacing all four timing chains. I know I'm running the risk of a trashed engine, but hey. I have access to the cams right now, I'll update with pictures later to help you get a better grasp of my situation. I'm getting conflicting answers on where the cam timing marks need to be, and whether they have to match on the left and right side. I've educated myself well on the car, and this is where I'm stumped. The closest I've come to for answers is the 4.0 Jag V8, and I am NOT trusting that as a source. I'd be insane to. Any help would be appreciated, and I'll work along as best as I can. Oh, and side note. I have no idea yet if anything is hurt yet other than the engine, it's still got a bit under a half tank of unleaded in it. If I can time it right and fire it, I'll burn that crap out and promptly fill 93 in her. Needless to say, this poor LS has been abused.