[dmjlambert]

Under the cab there is probably a short piece of fuel hose that goes between the hard line from the gas tank to the hard line on the frame. And at the engine there is another short piece of fuel hose that goes from the hard line on the frame to the fuel pump. You probably replaced the one going from frame to the fuel pump when you put in the engine. I suggest inspect the one under the cab and if it has not been replaced before you may need to replace it. If it is very old or maybe original be careful because it can crumble in your hand when you give it a squeeze and the gas will siphon out of the tank all over the floor or ground. Since you are going to be removing the sender to put a new sock on it, it means you will be disturbing the hard line that goes from the tank to under the cab and will cause movement at the fuel hose under the cab. The truck original fuel hose was not rated for gas with ethanol, but make sure your new one is. Since ordering a sock you may also need the fuel sender rubber grommet for when you put the sender back in the tank.
I'm not 100% sure on the fuel hose arrangement for 6 cylinder because I have an original V8, so my info may not be completely accurate.