Seeking the proper way to wire this old motor.  At the rear, inside
the usual place there are terminals numbered and short leads
connected:  6=red, 2=green, (cant see it)=black, 5=yellow.
Identifying info: AC Delco A2033 Series D-53 electric motor Thermotronic type A
The question is how to hook up to 110VAC.   (and how to reverse direction?)

I will bet that it is a 12v DC 3 speed motor. If it is and you hook it
up to 110vac, it won't matter which wires you use.

Don't mess with it if you haven't worked with motors before or don't
know what you're doing. It can't be a DC motor with that many outputs
unless you see electronics inside the casing. The ground from the plug
goes to black, the other one wire goes to red, and the third to either
green or yellow. Choosing yellow will go one direction, green the
other. In order to switch direction without changing the wiring you're
going to need a switch.