I did stumble across this as well, it looks like you can retain the original banjo housing but upgrade to much stronger axles/internals .
http://www.hotrodworks.com/product/m...le-conversion/
It requires 1940’s ford /Lincoln hydraulic brakes & backing plates which I just had a custom set for front &rear made for my roadster.
Although it may be overkill unless I go to a blown flathead where it’s making a significant amount of HP/tq to really start being hard on the trans/rear end