Leaking rear end 1967 Barracuda

Well, how much work do you want to put into this? For me- I can't work on anything without leaving it clean, showing that it has been fixed. This 7 1/4" is showing normal years of gasket seepage coming from the pinion seal, splines on the pinion shaft and the cover, and replacement u-joint. I would thoroughly clean the entire "pumpkin" area, yoke and end of driveshaft. My intent would be not to create a show car but to just have everything clean. Then I would replace the pinion seal and add some RTV behind the pinion nut/washer to seal any possible leaks there. Replace the cover gasket. Inspect the u-joint, if there is a zerk, lightly grease it. Now you should be fixed for a long time.