Loud pop and sputter on WOT? 68 318 Barracuda

I do have the idle speed screw adjusted all the way out so the blades are
There it is, those plugs are very confused.
Are you running fresh gas?
Are you saying what I'm reading? that:
The throttle blades at idle, are completely closed?
Where is the engine getting it's air from; or it's fuel for that matter? That ain't right.
Check that the base gasket is right for your carb.
Otherwise, the hunt is on!