There is likely an automotive shock that will replace what you have. Not sure if this will work for you or not but with my All Sports 6" Lift and HD rear springs, I installed shocks from the parts store.
I am also in the process of installing 3 leaf heavy duty springs on a 1992 Gas Club Car. Got the springs on, correct alignment with the bolt on the bottom of the spring, but am having a heck of a time trying to get the nut on the top of the springs to align with the hole on the bottom of the axle. What have folks done to solve this issue?