Cane Creek 40-series ZS44 lower headset assembly with crown race. For 44mm ID headtube and 1-1/8" steerer tube. Lightly used for less than 2 months - $25
I figured you might ask that. The 44mm headtube headset is what I had in my fatbike frame with the 1-1/8" steel fork and it would fit your current setup.
The 56mm headtube headset is the headset I mistakenly ordered when I was swapping to the tapered carbon fork.
I am running a Cane Creek 40-series EC44-40 now in order to run the tapered fork in my frame, and that should be the bottom headset assembly that you need to do the same, or the equivalent from your preferred manufacturer.