I just did a quick google search for the specs.
440: 320 ft-lb of torque @ 2000 rpm
400: 305 ft-lb of torque @ 3200 rpm
I think most people would notice a difference if that is accurate specs.
I used to use VR-1, it's got all the zinc you need (better off not adding any additives to it). But, being a racing oil, it's not designed to be left in your car for extended periods of time and does not have the ideal amount of detergents and corrosion protection for engines that are driven...
I've done a bit of research and I'd say that the best oil for any of these engines with flat tappet cams is Amsoil classic and hot rod oil. (Amsoil Z-rod).
I can't think of any reason why it would make a difference if the engine is running. Key in the on position with the motor not running everything is the same, except the oil pressure and charging current. How about the 4-way flashers? Do they work normally? I have seen where a bad ignition...
I don't believe the 1970 had the option of 14" wheels. Could you put 14" wheels on? Maybe if it didn't have disc brakes. But, 14" tires are really hard to find in that size and there are really no good options. You'd be better off sticking with the 15".