Well I finally had a free Sunday to tackle installing a used fuel sending unit out of a 1990 740 Turbo into my 1987 760 Turbo. Everything I have looked up and read indicates that these two cars use the same fuel sending unit. The main difference I noticed was that the newer replacement has a black plastic head (a HUGE improvement over the older metal head that rusted beyond belief). However, I am having a heck of a time getting the newer unit to seat itself completly flush in the top of the tank. They use identical gaskets and are the same size, but I can't get the newer unit to completely seat itself. The large plastic locking ring won't even engage any of the threads and screw down. I just can't get that last 1/4 inch of seating. I even resorted to spreading a thin layer of oil on the gasket and the inside rim of the tank portal to ease the whole thing in, but to no avail. I've tried twisting it gently, tapping it with a long pipe and hammer, and even swearing at it - but nothing works! I don't want to have to drop this whole tank, because that looks like an even bigger nightmare. Is there a magic Volvo dance that I need to do, or what???!!!