I have finished the trailing arms and these things are sweet.Thanks for the input guys.

I ended up building a jig,and clamping it down level to some metal sawhorses. I weighed down the horses with a couple cylinder heads and every other heavy object I could find to keep the sawhorses from twisting. When I put the pieces in I noticed they were a little twisted,1/8 inch at most.After welding them up they came out PERFECT.No twist at all.