Need help with fat bike and BBSHD install

[electricfun]

Trying to install a BBSHD into my RockyMountain Blizzard fatty. However came across a problem- the BB sizing is correct (100mm bsa) However because of how the chain stay splays out it wont fit!

I am going to put the 100mm bafang into another bike i own. However does anyone have suggestions for this??

 

[BikeRI]

Not a great donor bike. Would need the 120mm motor and use spacers.

 

[fechter]

If you had the 120mm BBSHD, would the chain line up with the rear sprocket? I have a BBSHD fat bike but the frame has clearance to the chain stay. A spacer would work if the chain line isn't too bad.