Parts searching will take weeks or months if you can even find a new part number to cross reference the old one. Split rims and widowmakers will be another issue, finding modern tubeless wheels will be $$$$. The brake system will have to be gone through and updated. Basically everything will be harder to find, more expensive, and a lot heavier.
I tell you all of this after dealing with my 67 c50, bought for $2200 and put somewhere in the neighborhood of $7000 in it and she still aint done.
Here is a thread that just popped up this week on stovebolt forum detailing the issues when dealing with the heavy haulers
https://www.stovebolt.com/ubbthreads...ml#Post1389598