If have the room then a open 1/2" spacer works out nice on standard Performer Intake when paired with a big Carb like the stock 750 or 800 Q-jet. About 440 hp can be made like this on a 430 or 455 motor and not have to resort to over 3.23 to 3.55 rear gears even with Intake durations in the 228 to 234 range on a 455 .
Hi Steve, Use the performer, and port match it to the heads... portmatch is worth about 10-15 HP on that type of build. I have made upper 500's HP with a performer/b4b several times. Those motors have put 3900 + lbs Gran Sports well in to the 11's at the strip. Here's an example.. 470ci Alum Stage 2 heads with level 2 port 10.4-1 239/247/113* hyd roller and supporting equipment 2" headers and big Holley Portmatched B4B nothing real tricky.. Now, we are not doing this motor here, I understand, I just put that up there to illustrate what a dual plane intake is capable of. JW
I would be mainly interested in one because it would look more like stock than a single plane, at least to locals around here