As others point out to me, when I sheared the cast key on my flywheel...... all it is there for is a reference alignment for the ignition, the compression on the taper hold things in place. Line it up and tighten it down on the shaft.
I added one step to hopefully improve the taper fit; I put some valve grinding compound on the shaft taper and worked the flywheel till it lost a few highspots; clean well and put together.

Just replace the bearings on the other and you have 2 useable engines.