Fox body hard to steer

Have a new to us mustang. It has the flaming river 15-1.0 rack (new) The car is set up with 75lbs bite 53.0 left 48.0 rear. Car is fast wants to turn left going slow but very hard to turn left at speed. Have not done the front end settings but it looks like from measuring with a angle finder on the struts it has about 3 degrees caster split The car is driving on the right rear. Last race used up the right rear the left rear was not hurt. I could move the right rear back another 1/2". Any other ideas would be greatly appreciated.

Thanks
David

Racing on dirt