The short list:
receiver needs: firing pin camming slot, extractor slot, 
Lever mod for extractor
extractor
complete Centerfire breech block
Hammer modifications

All need polishing and recasing.

In short save it as a percussion action and get a converted carbine , it would be cheaper (or trade someone).

Charles

I acquired a Shiloh Military rifle in 54 caliber a few years back for a real good price. I was able to get a Lothar Walther to profile a barrel in 45 caliber for me to match the the 54 barrel and then I sent the action and barrel to Rich at Schuetzen Gun Company for a conversion. He did a great job but did not add the projection on the lever so I had to send it back when I discovered loading the rifle required three-hands. The gun shot phenomenally well and I was very pleased with it until another project came up and I needed the funds for financing. 

I could have bought another rifle cheaper but I wanted a "conversion" with a big, welded-up percussion hammer and percussion style receiver profile.

The extractor cut was a little fun when I did one Had to make up the tooling to do the job.