The best spring shop I have everr dealt with is the one that Enterprise Engine Performance uses out in Ohio. I got my new u-bolts from them when they redid my rear spings to lift the back of my truck. I went to 3/4" diameter and extra long to fit my traction bars also. If I remember correctly I had less than $100 in the longer and larger diameter U-bolts which we used from them. Here is their number and address..... Andy
S&S Spring Shop
1755 Mt. Perry Road
Mt. Perry,OH 43760
1-800-619-4652