Cam is a big factor here.


In reality, it is the biggest factor in power, throttle response etc..

BUT that said, a small 4 bbl will be easier to tune,a nd easier on fuel. Probalby no difference in all out performance.

IMHO 600 is still too large for a stock 273 2 bbl motor. Holley makes 4bbl's into the 300's. 500 or so is plenty for that.