I have never seen the drive-line on a 1955-1st series 3100, but I think there was one propeller shaft (drive shaft).
Here is a page from the Specifications Manual. What rear-end are you using?
Is it a 55-1st 3100 rear end?
If not, how did you arrange/mount the springs?
Did you obtain the drive-shafts and rear-end as an assembly (with rear springs)?
Sorry about all the questions.
