I bought that 1967 144S and have been going through things with it within the last week since it has been sitting for 20+ years at the previous owners garage. It does turn over easily by hand with a 13/16" wrench at the crank but doesn't even click when you engage the key. The oil/amp idiot lights dim slightly when you engage the key but that's it. not a peep.
The battery is fully charged cleaned all the connections for battery and grounds. Tried rapping on the starter solenoid....nothing.
This has the BW35 automatic trans.so it could it be the neutral safety switch? or Could it be that ignition switch behind the key that has all the wires going to it ? For some there is a loose green wire there with no spade connector to go to near the ignition switch Strange ! Electrical problems are always soooo fun !