HID lighting

Would I get the same results from four 100wHPS bulbs as I would from 1 400W HPS? THe reason I ask is because I have only about four feet of hieght in my veggie room.

as long as you take care of the heat you should do alright. but you need to use them properly depending on the size of the op.
you have a 4' ceiling, is ok your gonna keep the plants short becuse 100's dont have the light penetration of a 400w.
maybe look at SCOG is good for lower wattage bulbs.

https://www.rollitup.org/view.php?pg=faq&cmd=article&id=268