Single 4bbl is the easiest. Use whatever 4 bbl you are comfortable with between 390-500 cfm.
for a 2x1 setup you wil want to switch to some Ford Holley 1 bbls instead of the Rochesters as the Holleys are about half the height. Make sure you get a matched pair, as the Holleys came in a ton of different sizes over the years.
