Looking for Resto Info 1939 Buick Century

Looking for a litle help. Restoring a 1939 Buick Series 60 (Century). Just bought a rebuilt engine from a 1937. Looking at converting to floorshift tranny, but the 37 tranny doesn't match up with the 39 driveshaft. Also, the 39 motor mounts are completely different than the 37... Possibly going to put the 39 bell housing on back of the 37 engine and use the 39 tranny. Any input or sugestions on this or converting the tranny to floorshift would be most appreciated.

Thanks, Jason