Stop in for a cup of coffee

Good morning everyone!!! So I have seen this question asked but I dont know if I have ever really saw an answer so I'm going to ask. What is the driveshaft length for a Duster with a 727 and 8.75 rearend. I had one cut down here a while back for my son's car but, I think (judging from the vibration) it's too short. I just measured the one that was in the car when I had the one cut down but, not sure what it came out of..