John,
i have the Blue Thunder dual quad intake with 2 600 cfm edelbrock performer carbs...simply the best setup I've ever had on any car.The intake is a dual plane.That means that the right bank of cylinders only 'sees' the left half of the carbs,so 600 cfm is all it'sees'.Whereas a open plenum manifold 'sees' the whole carb, if you have a 850 holley then each cylinder will see the whole 850 carb. The throttle response is outragous, 1/4 throttle and your gone,no bog. FFP [ford power parts in L.A. can get the intake for you.]The edelbrock carbs have a better low/mid range transition than holleys also.
Good Luck.
Perry.
