Well we gave it the old college try But looking at your pics again and got me thinking is your ram going to fit with the 120mm there anyway?
Is this a hot running system? Could you get away with using the 240mm by itself?
Seriously I'd drain it and take it to my local Automotive Radiator repair shop and have them fix it properly.
I've done this to several rads now with great success, the only downside is repainting them after the repair .