I run dual 500 cfm Carters on my 340 and love them. Engine idles great and has great throttle response. Been years now, no problems with them. I'm using the small port 273/318 dual quad intake for a 273 engine. Seals fine with fel-pro print o seal intake gaskets, get the ones that end in S, they got a steel core sandwich between, you can not split them by over tightening.
Yes, I know those old Edelbrock intakes are very rare but they do show up for sale once in awhile. And tuning is more work and you need double of everything, metering rods, jets but you asked for the best, I would not trade my set up for FI, for one I don't want high pressure fuel in the lines. There is good reason these newer cars catch on fire after a hard crash. 2nd, its really debatable if FI makes more HP, some engine tuners claim carbs make more HP, something about the ramming effect at high rpms. Fuel Injectors are sized limited, too big gives a lousy idle, too small, it can't flow enough at 7,000 rpm..then you have to get to dual FI for each cylinder.
There was good reasons dual carbs ruled the streets in the 1960's, yeah true, there was no Holley Dominator carbs back then either but those carbs don't idle so great on the street
