I am familiar with putting a late model rear end in a leaf-spring car, however, I would like to better understand how this is done in an older coil spring rear suspension car. To be more specific, I am a big fan of the 40 Olds. I have a "late model" rear end out of a 57 Chevy. I suspect mounting pads that line up to the trailing arms would be welded to the rear end. Do you then simply bolt the pads to the trailing arms using the best Grade 8 bolts you can buy?

Am I missing a bunch of stuff here?

Many thanks, great website!

 

A 57 Chevy rear is not an upgrade in your 40 Olds . It certainly isn't any stronger.
Unless you're drag racing the stock rear is fine . If you want a better crusing gear the center section from a 50's Olds or Pontiac with automatic will fit in your housing . Center chunks from 37 to 56 will interchange.
If you are planning on racing then a 57 Olds (or Pontiac) is the choice.
The brackets and mounts from the '40 rear will have to be cut off and welded to the '57 rear housing.

 

Did the 40 Olds have an enclosed driveshaft like the Chevy or was it open?

 

Charlie,

Many thanks for your input. Using the later center section for cruising gears sounds like a good plan. Any chance that axles exist for the 40 that would get me a 5 on 4.75 bolt circle ?

(Regarding the other gentlemen's question, I don't think the enclosed rear end disease spread to Oldsmobile.

 

A machine shop may be able to re-drill your axles and drums for the 4.75 pattern.
Be careful though, the center hole may not be large enough on the 4.75 wheels.