Here are a few pulleys still on the car.
The pulleys range in size from a 2" diameter up to a 6" diameter. I only use smooth pulleys, not pulleys with ribs, or v-belt pulleys. Each pulley has a different tone. I have several duplicate pulleys from the same type of car, and even those have slightly different pitches.
Once the pulleys were removed from the different vehicles I knocked the bearings out of them. Then I welded a large washer in the middle of each pulley to help mount them. Using old rubber bushings from shock absorbers I mounted all the pulleys on two threaded rods.
Eventually I would like to set the pulleys up more like a piano or mallet instrument would be, with the sharps/flats separated from the other notes. The pulleys can be tuned as well. One of my co-workers has a metal lathe and he has trimmed a couple of the pulleys for me. Cutting off 1/8" from the edge of a pulley changes the pitch by about half a step.