Driveshaft question

1975 Dart Sport, currently has a 904 with an 8.75 Sure Grip. I have a local 727 I would like to buy to rebuild and eventually replace the 904 with. I know the driveshaft will be different, but is there a standard length for this combination, or do I have to wait until the transmission is in and measure the distance?

Thanks in advance.
Author: admin