The perches on the rear end I've got are an inch too wide. I would rather move the perches in than move the springs out to keep plenty of room for bigger wheels/tires. I was told that if it is cast (my cousin can weld cast) the welds would be brittle and would break.
i just had mine welded on my 8.25, i can get you the weld specs, wire size and gas mix if you want. they are stonger now than they were. My 8.25 is 1970.