I have a 66 Suburban with the heavy duty rear spring package. I was told by a local who owned a Suburban, that it rides way too rough with the HD Springs. I picked up a set of standard springs from a 1/2 Ton pickup, with the intent of putting them in. It seems kind of strange to me that the HD springs have the center coils contacting. I have never driven the vehicle, so I have no idea of what the ride is like. Does anyone have any experience with the 2 types of springs, and which would work best? I do not plan to overload or tow with the vehicle. I have just one rear seat. The top picture is the HD spring, and the second picture is the standard spring.
Thanks for the help.

http://s1375.photobucket.com/user/rps2657/media/DSCN0903_zpsdiccuhvb.jpg.html

http://s1375.photobucket.com/user/rps2657/media/DSCN0904_zpssi2znres.jpg.html