[Shaun_Ashmore]

Do you think a 6.6 motor will fit in a sensei?

Shaun

[Kinver_Clean]

Have a look in the box to see if there is 3/4" space round the vac motor. If there is there is a good chance it will fit in. The height is similar/ slightly less.
You will have to make/obtain some brackets to adapt the mounts.
Check before buying that it has an inlet spout or not the same as the unit coming out.