Need shorter pitman arm

Since I put long tube headers on my 72 duster, my pitman arm is hitting when turned all the way right. I have the smaller spline and need a slightly shorter drop on pitman arm from original. Any ideas!?

Does anyone know a place where I can buy a shorter drop pitman arm with the 1-1/8 spline size?

Lastly, will the change to a smaller pitman arm put things out of wack?