that is not a standard Volvo carb, take my word for it, you will never see a marine carb with an external float bowl vent. That is a motorcraft automotive carb. Look for a Rochestor 2bbl off of an 888 Mercruiser, or a 2bbl Holley off the same

Remember my father years ago telling me on an I/O he had.
At the time he couldn't either find or afford a marine carb so he stuck a regular one on it.
Everything worked fine till getting up on a plane quickly or in rough water.
The end result was when the bow was pointed up (can't remember) either it would not let the gas thru from closing the floats or it would flood the motor. Either way once it leveled out it would run fine.
He quickly got the right one installed.