...somehow missed this thread...

Yup, we are a Hemi shop and, no I do not recommend using the 52-331 for your 49 car. Way too much involved.
Any of the Hemi-based Poly engines would be an easy swap and many have been done.
Read through this:
http://www.jalopyjournal.com/forum/threads/lookey-what-i-got-for-a-project-hyfire-poly.360864/


www.qualityengineeredcomponents.com
Early Hemi Parts and Tech
EarlyHemi and flat 6&8 trans adapters
***inventory clearance in progress. Nothing held back. See website.***