I'm dense guys, is there a tech article I can see pics? I get lost when you mention replacing the center section and grinding/welding spring perches.
The center section... the pumpkin, third member, etc (whatever YOU call it in your region). If you need to... google image "third member"... but if you need to do that, I'm not sure you should be doing this project yourself...
In regards to the spring perches needing welding. With the torque tube driveline, the spring perches (connecting part between axle housing and springs) are made to pivot for when the suspension traveled. In modern drivelines, we have u-joints and slip joints, etc. (those with more experience can correct me)
