Tire Wear, Front Only

I have a 1988 Mustang GT with 16 inch Waffle/Pony Wheels from a 94/95 Mustang GT. I have a five lug conversion. I have 225/50R16 in the front and 245/50R16 in the back. I installed these new tires (Kelly Springfield Evo Z) about a month ago. The rear tires are fine (wearing normally) but the front are wearing on the outside edge. The center and inside edge are fine. Does anyone know what is causing this? Here are the things I have done to try and correct the problem:

4 wheel alignment
New bearings
new ball joints
tire balance

What else could I try? I should mention that my car seems to sit higher on the front than in back and that I don't have any wheel wells up front (they were removed by the previous owner to make clearance for 17" tribars). When you look at the car when it is parked from the side, the front is much higher than the rear. I think this maybe a suspension setup (the car has excellent take off and weight transfer from front to rear).

I need help fast! My 2 front tires are almost ruined (the outter edges of the tires are getting really bad), but the rear are almost like new.

One final note: the 17" 225/45R17 tires I removed from the front and rear when I bought the car were also worn on the outter edges, only more severely.

Thanks in advance for your help!

The guy set the toe in when he did the alignment (I had approx 3000kms on the tires at this point). The car seemed a lot more stable and easy to control. At this point, the tires were already slightly worn on the edges. If the toe in was set correctly, would they still continue to wear the same way due to the fact that the tires were alreay partially worn?

I don't know anything about caster camber plates. What are they, what do they do, and what do they look like? Maybe I already have them.

My car is higher than stock in front. I did notice some round washer type pieces under the strut nut. Are these the plates you are talking about?

If the alignment shop said they set the toe in, should that have corrected the problem, or would I still need to add or remove caster plates? Would removing caster plates lower my car to the stock height?

Thanks for the excellent advice. I checked my tires again today (after driving almost 800 kms last night) and they seem to be wearing more evenly. They still look bad though. If it doesn't get better in the next few days, I will take it back to the shop. I have a feeling they gave me the ol' toe and go.