a903 to a230 swap in 64 dart gt 225 slant 6

Im currently swapping, what I believe to be an a230 transmission, out of a 72 duster. My dart had the a903 on the tree but I am now doing a floor shift with the a230. The a230 has a slip yoke instead of the pinion yoke the 903 had so i got a driveshaft also out of a 72 duster and it is way too short. Anyone know what driveshaft I should use or any other solutions?