For the oil smoke have a look at the oil pressure sender. It is not unknown for them to leak and spray oil onto the exhaust downpipe.

Low mileage cars are prone to seizing the advance mechanism, you should be able to grab hold of the points and twist them slightly, if not the spindle has seized. Otherwise as you suspect leaks. Timing gears are an issue on the 164, does all sort of weird things to the timing. Usually accompanied by a knock from the front of the engine, not always though. You can usually feel the slack twisting the crank with the plugs out. Not hard to change though, nor especially expensive.

Check the breathers aren't blocked causing oil leaks. Front autobox seal behind the torque convertor has been known to fail, more common than rear main, which is neoprene on a 164.

Personally the autobox doesn't bother me. A 164E has more than enough power to compensate for its inefficiencies.

Regards