We don't do a bunch of carburetor swaps here. The classic section may be more of a help but I know how to do it. This advise I'm about to give is for a cruiser or daily driver...not a race car.
If you go carbureted the classic harness will work. Other than carb and intake you'll need a holley external fuel pump for carb ( 40 bucks )...I think its 7 or 8 psi, a fuel pressure regulator to cut pressure to 5 or 6psi ( I used Mr. Gasket from a local parts store ...that's also where I get the holley pump ). A 500cfm carburetor, vacuum advance distributor, the gm style HEI distributor for the 302 is a little better and easier to set up vacuum advance curves. There are little springs and weights inside that control advance...they are available all over the place cheap. Running a roller engine you'll have to make sure the distributor gear is correct for newer cams. They come bronze...and steel.
You will need a set of thermactor plugs to plug holes in the back of the heads ( one each side ) where the emissions stuff connected. On a few of my street cars I ran edelbrock carburetors and they worked well for years. My last one got 26mpg on the highway cruising at 72mph. It was a 600cfm ( had a mild camshaft..e303 ) I think part number was 1406. I also used a single wire o2 sensor and an air fuel ratio gauge. Just a cheap one with the red yellow and green LEDs. Helped me tune the car to run it's best. Also bought from Advance Auto Parts.
This distributor is from Speedwaymotors.com. It needs a different gear to run in a newer HO engine. It's only 60 bucks. It comes with a coil on top. No more coil wire running from the fender apron over the front of the engine.