Which Carb Gives a Balance of Power & MPG?

i am in search of some mpg when i do the 400 swap in my duster. i had planned on using the 383 4 brl intake and my 3310, then i thought of going with a thunder series but decided i want a spreadbore carb. i picked up a brand new 440 truck TQ. its no too loaded up with smog junk and was cheap, never run. im just trying to find a cheap performer intake. i have only owned holleys and have no complaints. i only had issues tuning one 800 dp. otherwis it took time but they worked great when tuned, i never really cared about mpg though. always left them running a little fat. this should be interesting.