Will it fit?

Like said above no short tail shaft came in a Roadrunner unless it was changed out, I put a B-Body Hemi 4-speed trans in my 70 Duster and cut the trans mount crossmember and moved it back to accomodate the trans, it was not easy but that is all I had in 1981 when I did it. You also have to make sure the bearing retainer fits the bell housing as said above...