when you say hesitating, do you mean when you hit the gas to take off from a stop? that really sounds like an accelerator pump in the carb. to check, with the motor off, take off the air cleaner, open the choke plates and look down into the throat of the carb. manipulate the throttle linkage from under the hood, or have a friend mash the gas a few times. you should see a small jet of gas shoot into the carb. if not, your accelerator pump is bad.
for the 4v intake i would reccomend that you hit the junkyard and look for a cast 4v intake off a 318-60. these flow extremely well, and are often fairly cheap. if you feel that you must have an aluminum intake, i would reccomend the edelbrock performer, although the stock mopar 4v manifold flows just as well as the performer.
for a 4bbl carb, if you ask people what they prefer, you'll get all sorts of answers. some people swear by holleys, some by edelbrocks, some prefer a carter. i absolutely love my Rochester Quadrajet. it took some tuning, but once i got it right, i have never had a problem with it bogging and the throttle response is incredible. i've had my truck on some scary angles, and never had it miss a beat. be prepared for a chore in swapping manifolds, you basically have to take apart the whole top of the motor, but i have faith that you can do it.
Jake
