If I was to install two side by side electric cooling fans for my small block 350, should I or even can I still install my original fan shroud? This is on a 68 with the wide radiator (28").

Hummm....I have never seen that. The stock shroud is usually removed.
Most electric fans bolt right up against the radiator. Some (like the Windstar setup) have the fans built into their own shroud but are close to flush mount.
I have the windstar setup on mine with the large (33"??) radiator. You can see a couple of pics at my website. You also might need to upgrade the alternator to carry the additional load. I did the CS-130 conversion.
http://home1.gte.net/res096qi/71elky.htm
Chuck