Here are some things that may help:
1. The starter shown has no "R" terminal.
2. I don't know what they meant by the words "resistor (by pass)". Pointing to the top of te starter. If we knew, it would make sense what they were trying to say.
3. My exact same diagram in my manual says MODELS 3000 4000 6000. It does not say: MODELS 3600 4000 6000. Something fishy there on the diagram posted.
I could wire the whole truck from scratch with no diagrams at all. So lets get that all cleared up. I also have an FCC license that was in the past required for working on aircraft radios.
For listed items above.
1 It has a special terminal on the main switch for the by pass. If it is a normal chev solenoid that has an R on it.
2 The words resistor bypass are just that, its to by pass the ballast resistor to give a full 12 volts to the coil for starting, A HOTTER SPARK for lack of better words. There is a special small terminal on the starter switch for that wire.
3 This is the same diagram in the 55 shop manual, and also in the special electric manual the friend has.
Truckrolet is not so much asking a question, he is pointing out a problem.
Fibonachu:
There is no reason to run a resistor bypass wire to the ignition switch. They likely meant for the wire to go to the solenoid S terminal for starters with a solenoid. The diagram is messed up, and would confuse a non electrical person.
To understand follow from the starter and trace the resistor by pass wire, and there is no start terminal on the key switch of a pedal start truck, you push the start pedal you don't turn the key.
That wire needs to go to + on the coil. Simple stuff here not too difficult to under stand.