Unfortold "Carb Spacer" Power?

I think it's more of a matchign thing. If you have a mismatch, or something that falls where one can't tune it out, they might help. It's been my experience (and just to be honest, I have never dyno tested this to back it up...) that dual planes when properly matched in terms of carb size and camshaft suffer some throttle response loss especially off idle with any type of spacer. The 4hole helps boost the signal to the carb... but a smaller carb will have that same sensitivity and response. While a single plane intake, where it is sized right and chosen right matching the cam, and carb, and rpm range, can benefit by adding plenum and shaping the mixture because it will change the wave tuning in the intake, more evenly distribute the mix thru all 8 ports, and slow down the mix so it can make the turn smoother without seperating. The Super Suckers also smooth the turbulence found right under the throttle plate. It works like an airfoil and can increase cfms, therfore increasing power. How much depends on how bad the intake is to begin with and what you're doing with it. I've only used open spacers. Without a dyno, I can't see the benefit from simply swapping spacers.