Low fuel pressure with new fuel pump

My '71 swinger had enough room to mount on the frame just before the wheel well, that's forward of the axle
So theres space issues with mounting it anywhere near the rear axel. It’s an 8 3/4 which is beefier then I imagined it would be. But Behind the axel is the gas tank and air shocks. And in front of the axel theres the dual 3” exhaust tips that end right before the rear axel. There really is no room for it up there I don’t think.