all great comments above... this is a common occurrence in my world (boat drag racing) the first problem i see with your combo is the staggered jetting ,that in its self will cause erratic afr and rich and lean conditions. tunnel rams have equal length runners.. IE jetting should be square to start. the power valves need to be plugged as well.. i have found on 4150 style carbs turning the accelerator cams up side down works great and will save money on cams. squirter wise, i drill out the squirters with a .040" size drill to start out with,.but dont be surprised if you end up going much larger.... try this odds are your problem will be fixed worst case scenario you will need to increase the accelerator size to 50cc