Oil pump won't prime

if I tighten it to spec (30lbs) without a gasket, it jams the pump drive somehow. It turns fine in my hand and if I bolt it up hand tight. I'm thinking about going with a gasket to see if the extra space keeps it from sticking. (you know there are 6 threads on to use or not to use a gasket in here and we seem pretty evenly split. I may have found a convincing argument for the "use" camp) If not, I think now is a good time for someone to tell me what the bushing does for the pump drive and could this be my problem?

thanks again

lap