Can you order me a steering pump, Volvo Penta #838310?

The original power steering pump was Volvo Penta part number 838310 which is obsolete.

The complete steering pump kit 860881 (which included the steering pump 838310) is
also obsolete.

So what you have to do is to go over to a 855872 steering pump which is still available
and either re-use your pulley or purchase a new pulley 1219961 (probably better).