I have this old Hawk 610 analog diagnostic tune-up analyzer and no manual for it. I looked it up on a Google picture search and the taped section on the end of the wire appears to have a shunt across it.
I know someone who is working on a 1968 mustang with the original engine and he could use this if we can figure out how to connect it.
There's a clip on the wire by the shunt that looks like it could go around a sparkplug wire.
Black to ground or battery negative and red to the negative or points side of the ignition coil. I still use a Sears one on my car. Proper dwell makes a difference and it makes it easy to spot a worn distributor.
I don't think there is much use for this meter anymore besides a voltmeter. Most cars have a tach on the dash and I don't think you can do much with dwell unless you have points.