I have to agree the 390 Holley is more than just about any 235 street engine needs.
A 350 Holley 2 bbl(a 350 cfm 2 bbl is equal to about a 270 cfm in the 4 bbl cfm rating), is plently and by my own experience will deliver better low end,mid range and top end power plus better fuel mileage.The 4bbls are usually mounted sideways,the 2 bbl can be mounted either way.The slight "slant" of the manifold to carb mounting will have zero effect on performance.
