My experience is that the stock center carbs is kind of a restriktion on a large engine like a 500 cube lung ! I ended up whit a set of BG that flow equal on al 3 carbs and that work´t better for me aand one realy nice benefit is that the outer carbs have acc pumps and they are side hung float carbs whit lose jets on al carbs same as the old back in the days Direct Connetion sold 82&83 carbs that also outpreform the stock carbs if they are tuned corekt.