Carb too big?

A holley 1920 is like 160-235cfm depending on if you had a 170 or a 225 model. even a 350cfm Holley 2bbl is pretty big unless you are cammed and winding it up. The 390 vacuum can be had with a stiff spring so its secondaries will just barely open, keeping the velocity high and the demand in line with the fuel curve.