westerbeke 7.0bcg water pump pulley

This is a bit out of my area of expertise, so I'll pose the question here. I need to replace the pump pulley on the raw water Johnson pump for a Westerbeke 7.0 BCG The red paint cost on this part is unbelievable. Try $350+ As best as I can determine I need a single sheave, 3V belt size (3/8)...