Thats not a 4 link. Well to be specific that’s not a “parallel 4 link” everyone assumes when someone says 4 link.
a “4 link” is generally 2 equal length upper and lower forward facing control arms mounted to adjustable points chassis and axle for instant center adjustments and a track or panhard to control side to side.
That would never fit in there without backhalfing most of the frame.