another coil spring u-bolt qustion

[junkman]

Made me some blocks, going to order some u-bolts from summit. In the lowering block 101 post, it says 5/8 for a 3" axle tube 2" longer. When I measure mine I come up with 5/8, 3 3/8 wide, inside. Are u-bolts measured by the diameter tube they are suppose to go around, or the actual width between the legs. This is what I think I am needing
http://store.summitracing.com/partde...5&autoview=sku
I went to a couple places local a few months ago when I put a ford 8.8 in my s-10 and tried to get u-bolts. Honestly the people really seemed like I was bothering them and they didn't want to mess with it. I need some other things from summit anyway, and a friend is willing to split a set of 4 with me. Thanks for any help.