Yes on the spring change. The reason for the heavy right spring is because the rear housing tries to torque load (twist). The pass. side wheel wants to go up and the drivers side wants to go down. That's why open rear cars, no sure grip, posi, trac loc, always spin just the right wheel. This tries to correct that by evening out the load. Many bigblock 4spd cars were equipped from the factory this way. Your right rear will sit a hair higher, but it's not a big deal. Some people with just cruising cars like to to use 2 rights or 2 lefts for a even stance, but you have these and i would keep them.