Agree w/Kenny. Most likely a Sherwood pump, hopefully there's info in the casting to be sure
Thats an interesting setup. I've worked on a lot of crissys over the years ranging from 1950's vintage to present day. Never seen one from 1980 with a non merc oem sea water pump let alone painted red. Merc motors have been black for at least the early-mid 70's
Chris craft over the years has gone from taking mainly GM blocks and marinizing them in house as a chris craft brand marine engine to installing straight merc/volvo packages w/no alterations.
I'm wondering if this engine has some merc components and some in house chris craft components or someone put this together as a one off/custom.
Either way chris craft did use sherwood sea water pumps for many years so as said earlier, best bet is sherwood. If you can't source anything online check with a local marine repair shop, not a dealership. Repair shop will point you in the right direction, dealership staff will stare at you like deer in headlights