Heads

Is it a dog throughout the whole rpm range or just on takeoff? If it's throughout the rpm range there's something wrong that can probably be corrected but I do agree those heads with that cam (which is fair sized) in a small cube engine isn't going to have great takeoff. Especially since the converter isn't very loose and the gears are somewhat tall. To make what you have now work it probably needs to get into the upper 3k rpm's on takeoff so you need a much looser converter and steeper gears.