Those pictures they have don't look like the fittings you have. Those are not the push to connect fittings you put up pictures of. Site seems a bit suspicious too at first glance.

 

Yeah, I hear you. The guy that answered my email even asked for the VIN, and said they were the correct parts. I told him I would drop the tank and get a good look at the steel lines before I bought anything, especially at those prices. Looks like I'm probably buying a new hydraulic line flare tool shortly...Even Doorman shot me down...

...I can't see the ends of the steel lines above the tank, but if I had to guess, they have plastic push connect flares up top, and the kind you need the insert tool to get apart at the other end. It's going to be about a week before I can pull the tank. When I get it out, I'll upload some useful pictures and order in what I need to either replace or create them...

 

Any luck? I have an 03 GMC Savannah 6.0L V8 with the same exact issue just pop up. Were you able to confirm lines are what lines2go has on their website?

 

Right here: 2003 GMC Savana Series 6.0L Fuel Lines | GMC Savana Feed Lines - LinesToGo

These are the two lines that screw into the fuel pump on the topside of the tank, wrap around to the front side, and point out towards the front of the truck at the inside of the left frame rail. The ends of these are a push-to-connect fitting. If you can get the fittings off of the ends of the old lines without destroying them, you're good. If however, the lines forward of that- which go to the fuel filter and return line are damaged, you'll have to get creative with a nylon line repair kit. I was able to salvage the connections, but a lot of times, the ends of the tubing won't come out and you'll destroy the fitting trying to get the end of the line out of it...