Can I put a 1.5 in leveling kit on my 1985 ford f150 that has stock suspention with out having to get drop brackets for the i beams

 

You may have trouble getting it aligned (camber). You may end up with your wheels leaning out on top.
1 1/2" is pretty close to the limits of how much camber adjustment you can get out of the bushings (ball joint hits the steering knuckle).