Most Mercury dealers that I''ve dealt with also deal in Volvo parts.
I had an MD7A in my boat that I completely rebuilt before I realized that I really didn''t want an inboard. Volvo parts are expensive to say the least.
If memory serves, I think replaced the block
pump with an after market
pump from Jabsco.
Last I heard, that engine was still in service at a logging outfit somewhere in Maine.