4 blade vs. 2 blade alum. fan

[duke36]

Am currently running a 4 blade fan on new leakless pump installed by prior owner with no issues so far. Have read a lot of info. for the 4 blade vs. the 2 blade and some say no increase in air volume past the radiator. Is there any data to support this? Also, the pump has machine bolts to replace the studs/ nuts to the block. Can the 4 blade and pump assembly be removed without removing or tilting the radiator?