Picked up a "unique?" parts dart

15" wheels don't sound right to me, were probably swapped on. I dont know of any A bodys with 15's on them but I guess anything is possible. Is there a build sheet in the car?
Anyone know if 15's were an option for the A bodys?

The lower gears would make sense. 15's are usually taller than most 14's so a lower gear ratio would be helpful. 2.76 with a 26" wheel would be sluggish. 8.25 rear or 7.25?