Maybe. I've gotten away from the "traditional" holley carburetors, because they offer such little tuneability. I have a Quick Fuel 450 vacuum secondary four barrel on mine and have it tuned just right. They have adjustable idle fuel restrictors, high and low speed air bleeds......they're SO much more adjustable than the Holley ever were. Holley now sells some like that, but you're gonna PAY for it.
What I recommend though, before making such a big change to the 350 would be to follow everyone's advice and make SURE everything else is ironed out FIRST. Since this is the internet and none of us is there in person, nobody really knows for sure what's wrong, we can only give "good guesses". So I would try to make what you have work first. That will certainly be the most cost effective route. Then if all else fails, you might try a different path with the carburetor.
