The Holley SD will work well with what you have and fit easily under the hood. At your power level, I don't think that there will be much differencr between it and the 440-2D. If you have some left over space between the hood and air cleaner, add an open spacer. The added plenum volume will pick it up a little.

It's not just the fuel line size, it the whole fuel delivery system so its hard to tell. If you have 4.5 psi at the carb at the top of the rpm range you'll be okay.