It should be "the [..] receptor-antagonist ketanserin" (can't take a dose of a receptor). And the effect isn't complete if I understand it correctly. But higher doses or a more potent antagonist could block the psychedelic effects completely, yes.

I'm not quite sure if LSD has non-psychedelic effects that are mediated through other mechanisms (such as other serotonin receptors, or maybe the dopaminergic system). From what I seem to remember (from that neurology lecture, mind you (where I was high)), LSD has some cardiovascular effects – basically everything you may experience from a large dose of caffein: rapid heartbeat, sweating, nervousness.