Does Mitchell Overdrive From 29CP Fit a 31CP

[Nasukau]

Hi All,
I recently bought a complete running gear minus the frame out of an 1929 Coupe and the rearend has a Mitchell overdrive. I want to install the overdrive in my 1931 Coupe. Will this unit fit the way it is or is there a difference in driveshaft lengths of where the actual Mitchell unit sits underneath the vehicle from year to year for the Coupe’s since there is two separate pieces of driveshaft?