Coupling the electric motor up to the transmission was the first major design task. I did the design and most all of the machining of the adapter plate and coupler. I turned a hub that looks exactly like the ICE crankshaft end out of # 303 stainles steel. It has a tapered bore that matches an off the shelf split tapered bushing that fits over the motor shaft. Three 1/4" bolts pass through the front face of the hub and thread into the tapered bushing. As you tighten these bolts, the split tapered bushing clamps down around the motor shaft resulting in a rigid hub to motor shaft mount.. I used a dial indicator on the front face of the hub as I tightened down the bolts to make sure there was no wobble. After mounting the flywheel, I also dial indicated the flywheel face at a 5" radius and had less than .002" peak to peak.
The group of 4 small pictures show the tachometer sensor I designed. It's based on a hall-effect sensor IC from Allegro Microsystems. A small circuit board contains the sensor, a one-shot, and voltage regulator and resides in a 3/4" aluminum tube. A hole in the bell housing with a clamping block holds the sensor assembly in place directly over the flywheel edge. I cut a 1/8" wide by 1/8" deep notch at every 120 degrees in the flywheel outer edge so 3 pulses per revolution of the flywheel occur and drive the stock tachometer directly. The last picture shows the competed motor to transmission assembly. The motor just slipped right into place. It's great when things work out as planned!