There-in lies the problem....no part number in the Chrysler 70/71 truck parts catalogue or anything online....I believe that this power setup was a SERT equipment option in those years which you had to specify the SERT number off the VIN plate and contact Mopar for the numbers.
Does the truck have a SERT number? I've never seen evidence that power steering was ever available on a W100/200. I have seen SERT numbers on a few W500s that had it. That system was probably retrofitted by a previous owner.
