Awesome project. I've been daydreaming about something similar: pulling the driveshaft, and installing an electric motor at the rear diff. There's no center diff in my Loyale, it's either FWD or locked 4WD, so this could work. Maybe next winter...
Kudos on biting off such a big project! Keep going!
Also, somebody mentioned "a switch could be wired to activate the motor when the throttle is at 0" to capitalize on fuel cutoff. I haven't read the entire thread, but make sure this is not an automatic function. The last thing you want when you let off the gas is TORQUE from that motor.
I'd recommend a hand-throttle, or perhaps a sideways gas pedal for the electric system? I saw a video once of a guy who made a "foolproof" pedal system, where there was only one pedal. Pushing down actuated the brakes, and moving your foot to the right pushed against the 'gas' pedal. That way, there's no way to accidentally hit the gas instead of the brake. You could build a gas/electric double pedal like this, to mix your power.
Have fun!
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