I'm looking to confirm 100 percent that the bell housing on the hydra-matics '49-'56 or later interchange? Thanks!

 

Looks like 50 thru 53 upper housings are the same and 49 thru 53 lower bellhousings are the same.
In 1954 Olds changed to a 176 tooth flywheel from the previous 145 tooth wheel.
They also went from a straight pan to a slant pan trans.
See group 0.683

 

Great thanks for the confirmation! I thought so but needed to see it.

 

Also, could you share the catalog information you took this from. Just googling GM parts numbers catalog takes me in several different directions. Cannot seem to find a simple answer. Thanks

 

Available as a free download ;

1963 Oldsmobile Parts and Accessories Catalog (Chassis Edition) - ClassicOldsmobile.com

 

Thanks! Appreciate it!