Just installed a 3/4 drop kit from Mcgaughys on my 1500 2wd silverado. Had to cut out a notch on the front bed mounts to get the rear spring hangers flush with the frame. The front I used spindles and springs, and had to grind the top of the A-arm to be able to turn lock to lock without the wheels and tires on. Put the wheels and tires on and the lower control arms hit the wheels ! Tried 1/4" spacers behind the front wheels which gave me about 1/8'", but still not enough. Which also means I would have to re-stud with longer studs. I am using the stock aluminum wheels (15 x 7 ) which I believe have 4.25 backspacing. Any one have this problem or a cure for it ? Thanks !

 

Back around 2000, I did a 4"/5" drop on my '97 4-door Tahoe with stock 17" Impala SS. I had to trim the bottom of the lower a-arms to allow the wheels to make full lock-to-lock turns because of the deep backspacing on them. Never compromised the strength of the arms by trimming them, for just a daily driver truck.

Your problem is most likely the "small" diameter of the 15" wheels. Dunno how far you are from not hitting, but a spacer might work if it isn't too far. Otherwise you'd hafta get bolt-on adapters to push the wheels further out. My '02 isn't dropped in the front yet only because of the need for larger wheels to do so & my 16" tires are only 2 months old. No sense in replacing brand new tires!

 

I have dropped a few trucks in the age range. Like TexasSteve said noch the lower arm a little at a time and you will get it to clear. Or get bigger wheels