factory and dealer air compressor differences

ok.... /6 dealer air 68 dodge dart i have the compressor lines, condensor, everything to put the air back on this car. but i go to put the belt on tonight and i run into an issue with my p/s pump interfering with the tensioner for the a/c belt. also the belt is hitting the timing tab over the crank pulley. am i missing a spacer somewhere? oh and im fabbing the brackets to make it work with a 4 bbl and clifford headers. :burnout: