I'm putting a intake manifold with 3 rochester carbs on my SBC and instead of going with a progresive linkage which works with the center carb and at WOT the other 2 open up, I would like to find linkage that opens the first 2 carbs and leaves the last one to open at full throttle. It would be like running a 500 cfm 4 barel and when you wanted extra power, the last two barrel would open up. Have any of you seen anything like this?