Is this set up currently a single carb or duals now? You will find with a dual carb set up that carb tuning is even more critical especially down low. Float settings, fuel pressure tend to be the two things I see people have to much of in these faster NA cars for sure. Those things can cause WIDE fluctuations in AFR's especially down low. An AFR meter would quickly become your friend, as I say I do not see any excessive spin just laziness in first. But more info would be helpful.