The main difference on the kick down linkage is the bracket mounted on the back of the left cylinder head. The arm connected to the arm towards the card has a more offset to the right compare to the pnes on a 2 bbl engine.
The first three pictures showing how it looks on a 2 bbl engine. As you can see its a lot of offset.
Next is how it looks on a 4 bbl engine. The arm is also longer pn a 4 bbl arm. The reason is it will give too much travel.
Hope this will help you out.