How to unhook 4.3 fuel lines
 

2002 Blazer 4WD, 4.3L. Misfire on #4 cyl, 80 psi compression. I am trying to remove the RH head to inspect the valves. Question: How can I unhook the two fuel lines going to the intake manifold? Not the ones at the manifold, but the two lines near the firewall that are behind the mounting bracket. The hex nuts on the tubing are very difficult to get to. I cannot get my flare fitting wrench or an open end wrench on the fitting. I even tried a 15mm crows foot, but it too will not work. I am not positive of the size. It is about 5/8". Surely someone here can give me a hint. Please??

Never Mind
 

I found an old 5/8" open end wrench and I cut down the length to a little less than 4" and now have the two fuel lines loose. Stay tuned for the next question, please.

Yeah I cut down a 15mm line wrench but because line wrenches are six point I welded just the square hole of a 3/8 socket to the other end. Now I can flip it over essentially making a 12pt.