I'm trying to lower the rear end of my 1955.1 1/2 GMC but cant find any square u-bolts in my area. Are there any alternatives?

can i use round u bolts over the axle if i mount them under the brake line? will that give enough hold?

Do the square u-bolts need to fit snugly around everything or can they be 1/4in wider than the block and leafs?

thanks