Summit has the adapter plate for the single to two barrel for less than $20. Then while you are there check on the price of the Holley/Weber carb. You will find that it is cheaper to get a kit and try it. I'm not real savvy at carb stuff, but, I rebuilt mine in about 3 hours. Just take your time, and read through the instructions, twice if necessary, everything is in the kit, that you need, to do all of the adjustments.
If I can do it, most, everyone else can to. You will also need a couple of cans of carb cleaner, use it liberally in all of the nooks and crannies.
However the choice is up to you, as to which way to go.
good luck in your endeavors and don't hesitate to ask for help as you get along.
