Thanks Guys --- What appears to be cast are just the spring mounts. And they may well be cast steel, not iron. They are definitely magnetic and "spark" like steel but do have a crystalline interior like cast. It is also necessary to alter the width of the perches. I am hanging original replacement springs which are 2-1/2" wide and the 1998 Dana/Chevy had 3" so metal had to be removed to fit the original sized U-Bolts. As noted, the perches were welded onto the tubes so I am hoping that might indicate steel that can be welded "normally" but would still like to try and anneal slowly to avoid any possible problems with cast metal of any type.
Off to read up on Grigg's list...thanks again and I'll let you all know what I discover.
