Install a solenoid to the throttle arm. When you kick on the A/C, it
will boost RPM at any rate you adjust the solenoid in the bracket to.
Solenoid should be easily found at parts store. Making and adapting the
bracket to hold the solenoid may be tricky, but it may be a piece of
cake too. Anyway, that's what I would do.

Hank

Don't take this wrong, but if you bought a "complete A/C kit " from a
wrecked car, why did you not also get the throttle kicker from that car as
well? If the donor car was a different model and did not have such a devise,
then what makes you so sure very thing else is going to fit exactly as it
should on your car. I only say this because I have been down this road more
than once when some of my students have wanted to do this on various cars in
the past. It has always turned into a nightmare because unless the two cars
were exact identical makes with all the same equipment, there always turned
out to be some reason the job required a lot of engineering which was beyond
the capabilities of the students.  I was usually able to engineer some way
for the job to get done, but it often required a great deal more of my time
than I could spare along with the other duties I needed to take care of.  If
you have very good mechanical aptitude and excellent engineering skills
along with resources to all the necessary machine shop facilities, I am sure
you will figure out something. You might even get lucky and run across
someone here who has actually done this before on your same make and model,
and has just what you need, but I doubt it.

Having said all that, I can only advise that your first quest should be a
better repair manual that is more detailed on the operation and service of
you model car. Perhaps a copy of the manufacturer's repair manual. Once you
understand how idle speed is controlled and know the parts locations, then
it might not be to difficult to accomplish the task.

BTW, if you are going to get some good help with this project on this forum
you should probably post back with a more complete detail of the car. Such
information as the size engine, type transmission. and other optional
equipment could make a difference on what you will need.

Good luck and let us know how it turns out.

On carbureted models it has been my experience that there is usually a
vacuum operated dashpot/solenoid that opens the throttle slightly to
keep the idle speed constant when the AC compressor kicks on. I saw
this setup on an 80's datsun and I have a dashpot/opener combination on
the monster feedback carburetor on my 88 mitsubishi pickup. Usually one
of the manifold vacuum taps feeds to a vacuum solenoid, which is
electrically in series with the AC compressor. Compressor kicks on,
solenoid opens, which passes vaccum to the dashpot/solenoid, which then
opens the throttle just enough to hold the same idle speed. Most have
an adjustment via pushrod or stop screw.

Adapting your own version of this system into your vehicle is going to
be a big challenge. I would suggest scouring the junkyard for the parts
that are for your specific model to make the idle-up work properly.
Alternatively, you could just raise the idle speed 100-150rpm and
forget about the load of the ac compressor. Sure, the car will idle a
little fast without the AC engaged but that's a small price to pay for
having it all 'work' without a bunch of work....

Chris

Have you looked around the throttle plate(s)?  I don't know if it
attaches directly to the carburetor or to hoses on each side of the
plate(s).

Increasing the idle speed by 150 RPM may be enough because my 1986
carbureted Corolla had a vacuum-operated diaphram that raised the idle
speed that much when accessories were turned on.