There is a slight taper. Once you get the weight off the springs they will come off with a little persuasion.
AC Delco still makes the replacement parts with the correct bushings, bolts, soft gasket, washers, etc. The nuts aren't the same as original and are slightly thicker, but otherwise, it's all the same as the old stuff.
Amazon has them for around $24, much cheaper than the truck supply houses. AC Delco 45G13044
