actually mine worked very well out of the box w/ very little tweaking. I have since added more compression muuuch better heads and a solid roller cam.. that's when the tweaking started.
The OP has a 500 inch engine , they carbs are calibrated for something that is 60 cubes less , so tweaking is a given ...
yup before he bolted them on he should have upped the squirter, upped the jets, maybe dropped to the purple springs and went w/ a 4.5PV...