A B7100 is not the easiest to swap from dyno to alt for 2 reasons, space and drive ability.
You can mount one to the side, that will make you either alter your side panel or remove it all together, add brackets and then a longer belt.
Or you can mount it on top of the engine tight to the injection pump.
You will need to make a complete set of brackets rework the drive pulleys to run it, as you will need double pulleys at at least one connection point to drive the new alternator.
With either install if you want it to work 100% efficiently without the draw of also still turning against the magnets of the dyno, you'll need to disassemble the dyno and gut it, and reassemble it as that is the fan drive.
I chose to add one to the side as it was simple and painless, and I had already used up the space above the injection pump for a stop solenoid so it shuts down with the key instead of the throttle.
It just required cutting a hole in the side panel.
It's been that was ~5 years and never an issue.
At $322.44 you would really want it, and you would still need to spring for the voltage rectifier / regulator to run it.
