what power steering replacement could get a 1964 Toyota pick up?
That is a major project. You have to install a power steering box and a pump on the engine along with pulleys and idler wheels. You will also need to fabricate a custom steering linkage to the front wheels and for the steering wheel. I am sure it is possible but why do you want too? I would look at other small cars that have a steering box, not a rack and pinion. Junk yards will be your best bet.