Front Tires Are Wearing Prematurely

I am running 155/80 15's on the front the problem I am having is the front tires are wearing very badly in the inside. The first problem was that it had drag shocks on the front and the alignment guy couldn't get the front end to set at the same height. So after I replaced the drag shocks with regular shocks it seems that the alignment guy still was having issues getting the front to stay at the same height. The tires still seem to be wearing. It has had a front suspension rebuilt before I got it and the previous owner put SSBC front discs on the car. He did put 1/2 inch spacers to keep the 15X4.5 rims from rubbing. Could it be the the tires are set out too far with the spacers or something in the suspension. I compared the front suspension with another dart and everything looked the same.