360 driveability problem

i agree with the carb trick. leave your four fingers slightly open and smother the carb, mainly the two front bowls. if it picks up, your lean. if you don't have the cam specs, do you have access to a dial indicator to check lift @ lobe? this will help narrow down what the cam specs might be. im thinking you have the timing coming in too fast since you say the power starts around 3000rpm. what is the stall on the converter? if your powerband starts @ 3000rpm, your total timing needs to be at least by 3500rpm not 2500rpm.