Watching Roadkill, the episode with the "vanishing paint" challenger, they turned that car into a road course machine. They mentioned that they welded a plate to the front hanger that went inboard and mounted the shackle mount to that. That allowed them to move the springs in and get more tire clearance. Now, if you are a member of MotorTrend streaming, you can watch the episodes where they actually build the car. That show is called Roadkill Garage. I think there are 2 episodes for the build of that car. I don't subscribe so I haven't seen them. I thought that was an inexpensive way to take care of the front mount.

Or you can do the opposite too, weld a plate to the outer side so you dont have to mess with the mount. Just drill 4 new holes to mount to the frame. I think this is the way they did it, if I remember correctly.

Roadkill S4 Ep. 16