Gear drives can not be used on an engine that is equiped with a knock detector. It seems that they send harmonics through the engine that the sensor detects as knock. That is reason enough for me to decide against using one.
To kep your drive from eating through the timing cover you need to use a timing cover that is equiped with a cam button. An adjustable button will be perfered. You may want to think about using a bearing between the cam gear and the block too to fully locate the gear.