It might be cheaper and easier to get a 5.0 mustang motor with a smog pump and install it.
Nope...
Will not fly with the Smog Referee... Newer Mustang motor in a Bronco will have to have smog components of the donor Mustang that function.
Now if he paints it ford blue, changes valve covers, keeps the V-belts, hooks up the rest of the 77 smog equipment, yeah he could make the air injection to the back of the E7 heads work... But then he needs a single outlet port air valve and to be more educated than the Smog Ref. I know I did it.