Hi SageCuda,
I just upgraded my front brakes on my '71 Cuda from 11" front drums to Wilwood disks. The kit I used was 140-2721. I bought mine from eBay for $510. They were a kit someone bought but never installed. The Wilwood.com site lists them for $612.
Anyway, I found the install to be very easy, even with my relatively limited knowledge of suspension parts. The 140-2721 kit mounts right up to your existing drum spindles, so no need to swap them out like I see on most of the different kits you provided links for. Also, the quality of the parts in the Wilwood kit was outstanding. The most difficult part of the swap was finding a safety wire spinner tool. A friend of mine let me borrow his, but even for my first time doing it, I didn't find it to be that hard.
I am still using the same (non-power) master cylinder I had before, but I may upgrade it to one that is more appropriate for disk/drum apps.
If you want to chat about my particular install, you can email me at
bjasonsmith@juno.com. Best of luck.
Jason