I would make sure the centrifugal isn't coming in until maybe 4500 or so as it might be what is making it doggy. Get another set of weights and drill an 1/8" hole in the end of them but install one at a time. That will tell you where you need it to come in. May need heavier ones or even leave a spring off. I would use 4.30s. Then a looser converter if you wanted more.