Hey guys, I have a 67 mustang fastback A 4 speed transmission conversion was done but now the driveshaft is too long. The place that has it is saying the driveshaft is a step down meaning the diameter/ujoint at the rear is smaller than the front. I am looking for a new driveshaft but im not sure how to get one with this step down feature. Is it required that it has a stepdown or will a solid 3in shaft work? If it will what joints do i need at the end? Any help would be nice, every step of this process has been a headache.