I think you'd have about as much luck as trying to make a Ford piston work in the Gen I.
Gen I 350
1.560" compression height
0.927" wrist pin diameter
Gen III, IV
1.338" compression height
0.945" wrist pin diameter
I don't think the valve reliefs will line up either.
I've done this kind of hokey stuff in the past and have ended up spending more money than if I had used the correct parts in the first place. Sell those pistons to someone who needs them and start fresh is my best advice to you.