Greg, Popping the pumpkin out of an 8" rear isn't that bad,like Thack outlined above. Have the filler plug removed and just pry it open gently at the bottom until it drains Get ready for some STINK ...30 year old 90 weight will smell up the place for weeks. Get it in a sealed container asap. Once it has drained, then you can remove the pumpkin. It probably weighs 50-60 lbs. Clean the gasket surfaces, and reinstall it with new gaskets. The only problem I had with mine when changing the gear was that the bearing on the passenger side was in there tight (probably too many one-wheel smoke shows before the car got the locked rear). Went to Auto Zone and borrowed an axle puller for that side.
i think some early 70's have the 7.5'' rear while every other mav out there has a 8'' stock 7.5's have a removable inspection cover on the back but 8's have a solid housing with a removable carrier that unbolts off the back, just like a 9'' i think 2.79 and 3.00 were the only avaliable gears for 8'' mavericks, 6 or 8 cyl