1967 chevy lwb with coils help me

[willis0107]

ok so i replaced the front coils yesterday and when i went to remove the rear coils the only thing that i did was break off one of the bolts that goes through the trailing arms and holds the coils in place i am trying to lower the rear end by using coils but i am now thinking of replacing that bolt and using blocks on it to get my four inches of drop in the back what have you guys done as far as dropping these trucks what did you use i want to stay away from air bags as i will be moving to the midwest and will have to drive gravel roads from time to time