I'm also still learning.
I had what was called a 1/4 cam in in my 173 VH 5spd. This was supposedly 1/4 way to being a race cam (or so everyone used to say), in other words a mild cam. I had the standard Varijet carby rebuilt and Perry Headers/extractors.
The idle was lumpy enough for me to be asked quite a few times if it was an eight, at least until I gave it some revs and then there was no mistaking that it was a six.
The economy improved quite a bit and even driven with a bit more gusto I got 28mpg (10L/100km) in the city and could easily get 35+mpg on a country run.
Just with those mods my 0 - 100km/h dropped by nearly two seconds to a supercar like 9.8 seconds (that was considered good back then).
So I was happy with the standard carby and the car remained very reliable.
There are a few different carbies you can fit like Webbers, Twin or triple SUs and twin or triple Strombergs that may provide a bit more go but the strombergs and SUs will use a fair amount of fuel and need tuning every weekend.
Everyone used to fit a 350 Holley. In my opinion and from experience unless the motor is fully worked they are too big for a Holden six. People who had them fitted would get them rejetted when once they realised they got only 10mpg and had no guts. The end result was an expensive carby that offered less performance and efficiency than the standard carby. The Holley 180 was much better suited but were hard to find.
The Holley was the thing to have though so everybody got one.
The noise they made convinced many that their cars were going quicker.
Sorry for the waffleand not much help. Because I haven't looked into it for so long there may be many other good choices these days.
There will be someone here who knows.