The only difference is the lower control arm steel sleeves on the S-10's use a combination of ID's where they mount to the frame. Some have 1/2" on all 4, some have 9/16" on all 4, some have a combination of each on the same truck! Not sure how GM decided on what sizes to use or in what years... but they vary. We've come across the same year trucks that have different sizes in each... not sure why or what.