I don't see why it wouldn't work.
A little trick to help save you from possible aggravation from deformed threads where you ground the shaft down is to put on a nut. It will help clean up the threads making it easier to install the clutch shaft back on. You would put a nut on the shaft, grind...
Like the brass collet and flywheel on a traxxas for instance. I did the same on an old Aquacraft engine.
I was only thinking if the original engine didn't require that spacer shouldn't it already be a collet and taper fit flywheel?