Thats as dumb as asking what the difference is between 260 CFM out of a 360 head and 260 CFM out of a W2 head. It ain’t even close.
Im beginnig to figure you out. You must be dirt poor and can’t afford squat so you turd buff junk and then claim you are smart because you can get 240 CFM out of a sub standard casting.
Only poor people do that.
Save up some money and buy a better head to start with. You will NEVER ago wrong doing that.