I have found that a small four barrel gets better fuel economy than the stock two barrel. (kinda depends on your go pedal too!!)
Living near the mountains and using my truck as a daily driver, I avoid Holley carbs, as they CAN be finnicky with weather/ altitude changes. I run an Edelbrock /Carter with the offroad kit and am extremely happy with its performance.
Be careful when choosing a new intake manifold as the medium and high rise intakes can cause you grief with (factory) hood clearance issues.