I need to switch to the large bolt pattern on a 71 Swinger. I can get an 8 1/4 axle from a 73 318 Dart with automatic. (I thing it is a dart, it is a two door Duster style body with fold down rear seat.) Does anyone know if the drive shaft from the 73 will fit the 71 Swinger after I swap in the 8 1/4"? I cannot go measure the Swinger, it's out of state and I want to grab the driveshaft if it will fit and save me the custom length shaft hassle. Thanks for any insight on this.