After you install it the only problem that you may have is the hammer nose being too long. Meaning it will keep the hammer from giving enough force to the transfer bar and then the firing pin won't go forward far enough. If that happens just file (lightly) a few thousandths off of the hammer nose. It doesn't take much and you don't want to pinch the transfer bar between hammer and frame when the hammer is at rest. That is one way to break the t bar.
Deadeye, I installed a SBH hammer in this Liberty 357 BH. It appeared to work but when I tried to fire it, there was barely a mark on the primer and no bang. I had to grind off about .020" from the top step of the hammer before I got a decent dent in the primers. Ruger made some slight changes in the thickness of the transfer bar so a new SBH hammer would probably work in a new Blackhawk without any modifications.