1999 Oldsmobile Cutlass/Chevy 3100 Return Line Stuck in Fuel Rail

Hey everyone I’m excited to be joining the forums here. I’ve been watching Eric’s videos for a while but I never realized how cool his website is until recently. My question is about my ’99 Cutlass which has the GM 3100 engine in it. I’m working on replacing the head gasket/heads if I need to and getting the block pulled and checked, but I’m having a little problem with one of the lines being stuck in the fuel rail. It’s secured with an o-ring and definitely not wanting to come out after I tried a bunch of things that wouldn’t risk breaking it. Fortunately I was able to remove both of the metal quick disconnects after a few hours of struggling and I do have the fuel rail removed, but I want to get that line off to be able to replace the o-ring and lube everything up. I’m cleaning the whole fuel system because the car’s been sitting for around 4.5 years. I’ve thought about filling up the part of the fuel rail near the o-ring with a penetrating oil and seeing if that helps.