This is a two piece design that is fully machined.  This design eliminates the need for any welding.  We have discovered other brands that use a welded design have warping issues where the plenum bolts to the head.  This is the solution to that problem!

If your 7.3 is a later model year that runs the 10 bolt plenums these will work by drilling out the dimples in the Obsession Diesel Plenum.