My "opinion" is to use the straps with, as you mentioned, U-bolts going the other way. Its a loooong story but in the beginning a friend of mine fabbed me a "plate" which I think is best but when I put it on I didn't have the hole for the spring center bolt in the right place and I had the holes for the U-bolts to "wide" or rather not close enough to the edge of the spirngs. So, I started over and made a set of straps. If you use straps just be sure to tighten them EQUALLY because if you run a nut up a lot farther than the other it can cause the end of the strap to not be "flat" which will throw the shock mount at a different "angle" on the end clost to the tire.

I'm still not sure if you replaced the ENTIRE rear end of just the pumpkin...... but on mine I used the original housing, cut off the original swivel brackets, bought a set of perch blocks form the dodge dealer, (Pm me and I'll send you the part #).

I might add that the center bolt that goes through the springs is not CENTERED so some positioning of the rear end is necessay whether you are using the original housing or entirely different rear end. Since I am using my original I turned my springs around and put in new bushings. Turning them around helped put the spring center bolt closer to the center but I still didn't like the way the tires looked in the fender opening so I moved the axle forward 3/4" to get it to look good.
I'm talking panel truck here so a pickup may be different?

1937 Chevy Pickup
In the Gallery
1952 Chevy Panel
In the Gallery
More photos
1950 Chevy Coupe
Pictures!

I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile