I have a 1965 dodge dodge dart with 225 slant 6 . i got rid of all the slant 6 suspension front and back. I doing a front disc brake conversion form parts car 1974 duster. Im still using my factory lower control arms and bought a V8 drag link to use as well. I'm in the process of changing out the idler arm and pitman are . i ran into a snag on the pitman arm. Moog or any other top notch brand does not make a pitman arm for my car? So im left with dorman or from O'reallys these 2 parts. Proforged # 103-10053 32 spines and measures 5-5/16 center to center. Rare parts # 20112. 32 splines and measures 5-3/8 center to center. I didnt know there was 2 different sizes or is O'reallys just dumb asses ? and how do you measure center to center on a pitman arm??