I've owned both 440-6 and 340-6 cars. From my experience, the small block was overcarburated. Thats a lot of CFM for a 340-360. It did not run bad, but just felt like the throttle response could have been better.I played around with it quite a bit, but just never could seem to get it spot on to my liking. Now if you ran a stroker small block, that might be a pretty good setup. As far as visual impact, the only engine with more under hood appeal is a hemi. The six pack setups look cool, and when those outboard carbs open up, they have a unique sound all thier own.
They are easy to setup, as the outboard carbs act as basicly vacume actuated secondries. They open via vacume pods, and you can change springs to either slow or speed up the opening rate and point. The big blocks take well to them, every 440 I had with a 6bbl setup on it ran very well. A well tuned 6bbl setup will give most hemis a run for it's money till that top end hemi charge kicks in.
Bottom line, if you just want performance and bang for the buck, buy a 4 bbl. If you are looking for under hood impact, get the 6bbl setup.