There should be no gap. Either that spindle has the wrong size tapered hole (which is reamed at seven degrees), or your ball joint is off a pick-up truck as it has a super sized stud coming out of the ball joint (you, pick).
I'm guessing you have a brand new aftermarket dropped spindle. If so I would be showing the guy that sold you that part your gapping photograph and ask him what is going on.
Speedway sells reams to open car spindles up to accept pick-up truck ball joints (which are bigger and stronger for racing). But before I got creative I would find out what is supposed to be there.