The vacuum is reatively important to an engine's operation and lifespan as it promotes ring seal and plays a crucial role in evacuating condensation/unburnt fuel vapour. Furthermore, if you didin't have the vacuum assist with the crankcase ventilation, the parasitic pumping losses from the air turbulence will rob you of some power. I know of a number of race cars that run vacuum pumps (when allowed) into the crankcase, and all the super sport bikes have ports drilled between the cylinders to reduce these pumping losses.

You can vent it all to air (thorugh a catch can - dumping it staright form a hose would be IMHO rather dangerous as there is a real possiblity of fire), but your engine performance is either not going to be improved over stock or will be worse than stock (with or without an AOS) that is still providing vacuum to the crankcase.

 

http://www.gzmotorsports.com/why-use-vacuum-pump.html

A few of the LS7 guys are using these.
Overkill for an oem m156 Diabolis?