A little more confusion here. But first, thanks for all the input re vacuum lines, etc. As I am sure probably all the world knows by now I have installed a 300D into a 240D chassis, which I don't think should be all that uncommon. It was not a direct plug-in and, of course, all things are not the same. There is a magnetic pickup just above the CS balance wheel and it plugs into a plug on the left wheelwell on the 240D. Since the 240D was not equipped with a tachometer, what in the world was it for? I haven't really tried to run down the wiring yet, but ye old local junk yard, excuse me, automotive recycling center has an instrument cluster with a tachometer in the same place mine has a clock. I would like to install it. Is this magnetic pickup what drives the tach, or does it come off somewhere else?

Thanks for this, past, and future help.