Steve,,,,
You can do this fairly easy ,,,,, but,,,, be prepared to spend a bunch of money..... all of the items for the factory correct set up have a hefty price ,,, no matter what it is.....
You will need to get the intake,,, the factory correct carb numbers,,,, the factory correct air cleaner assembly.... [I have seen the correct nut that holds the lid on go for as much as $65] the carb linkage for a factory correct is different from the aftermarket ones.... the correct kick down switch and the bracket that goes with it,,, the right fuel lines,,, and the right power brake fitting and hard line..... the going price for such a set up is usually $1500 or more.... and,,,,, some guy can come along with a good single carb set up and out run it..... assuming the same amount of power for each engine....
Then there is the other side of the coin,,,, you have 2 carbs to rebuild,,, linkage to adjust,,,, ect....but,,,,, the ''wow'' factor is high.......also ,,, in order to get the full potential from the dual carb set up,, you will need the ''other stuff '' to go with it.... [the factory did not just set 2x4's on a engine and let it go down the assembly line] you need a good hot cam,,,, the performance distributer curve,,, and the low restriction exhaust system.....the 3.42 diff with posi,,,, all this must be there or the 2x4's will not perform as it should,,,,
back when I was looking for a riv to buy, I drove a riv, that had the 2x4's on it,,, I could tell when I started the car up and did a walk around listening to it , that it did not have a hot cam and did not have low restriction exhaust,,, and I aint talking about the loud aftermarket types like flowmasters ect....,,,, On the test drive , I let it get warmed up good , then stepped down on the accellerator and the car was a stone..... either one of the cars that I have now would run circles around it..... then the guy was miffed because I offered him less than what he wanted....just some ideas,,,, Doc