I am not trying to beat on your combo.However I don't think a .509 cam,2500 stall,and 3.23 gears is a good setup(especially for two fours).
I don't know if the offy is a high rise tunnel ram or one of their low rise dual quad manifolds.The low rise ones are not that great from what I hear(no exp.).Either way I would be looking for small carbs such as two holley 450's or carter 500's.Vacuum secondaries would be ideal.
With that cam it may be a bear to tune right.
I would consider going with the edelbrock ch28 and two 500's.Sounds like a really cool car.