If you are looking to position it "restore correct" I cannot help you. If you can't figure out how to hook it up, then, maybe
You have a shop manual? Download one here
http://www.forabodiesonly.com/mopar/showthread.php?p=1970088617
Which amounts to here
http://www.mymopar.com/index.php?pid=31
and the download link:
http://www.mymopar.com/downloads/servicemanuals/1965_Plymouth_Service_Manual.zip
If you have a stick car, the relay will only have one "push on" terminal, unless someone has used the incorrect relay. If you have a stick and the relay has two "push on" terminals, simply ground one. Automatic cars have two and they are interchangeable.
The "square" looking terminal only has one wire, and this goes down to the starter solenoid
Any other wires will have a 3/8" eye end and these all go to the big battery stud terminal. From battery to stud, and from stud to starter. Will be at least one other wire coming off that stud which provides power through the bulkhead to the interior, to ammeter circuit.
Below is from the 65 manual
At the relay, the push on terminal at top right is wire S4, look at the chart, is brown no 16. This goes down the firewall to the neutral safety switch on the automatic. If you have a stick this will be grounded
Bottom right, "Start" is the second push on terminal, wire S2, look at the chart, black / yellow, goes through the bulkhead connector and is the start wire from the ignition switch
Middle, is the square solenoid terminal, wire S5 only goes one place.....to the small screw on the starter
Left, is the "battery" stud. A1 should be fuse link going to bulkhead
H1 to horn relay
Last one comes up from starter (battery)
(Some newer models run the battery to this post, then down to starter. Same thing)
