[Ironangel]

LMC has the coils for BB as well as SB, front and rear as well as front and rear 4 spring kits depending on what motor and even variable rate coils... http://www.lmctruck.com/icatalog/cb/full.aspx?Page=62
I ran the stock 1/2 ton SB springs in my 1/2 ton BB truck with no ill effect in handling. The BB did squeeze another 1" drop down but they had plenty of room to function with no coil binding. The softer rate actually helped plant the rear on high rpm launches at the track...If you dont have a sway bar up front then you will need the heavier BB springs...Im referring to 2wd C/10's w/coils only...PS Mike C is correct in that 3/4 and 1/2 ton springs interchange. They're practically identical although the 3/4 ton springs are a larger diameter rod than the 1/2 tons. I installed a set of 3/4 ton coils in the rear of my other 72 C/10 towing rig. It already has a set of factory overloads and I installed a heavy 14,000lb class-4 hitch...So it thinks and pulls like a 3/4 ton...