There's lots you can do with the carter you just can't 'buy' the parts to modify it like a holley. Any carb can be modified because at the end of the day its all physics that determines how it works. As an example if you wanted to introduce air into the main well to slow the fuel down how would you do it? Would you stack 3 or 5 holes on one side or would you have a cylinder where you could place all the way around and have more holes but smaller in size so that the mixture is more homogeneous?
When I first got into carbs I asked Shrinker what I could do to improve the the design of the Holley and his response was: "Fix a Holley and it will work like a Carter"
And this:
Carters design philosophy is similar to other manufacturers. That is its to size the booster and channel so that there is no need for air bleeding. Air bleeding (emulsion) is a crutch to enable cheap manufacturing to function across a wide range of applications. A carby can be designed so that there is zero emulsion. People think that emulsion air creates some form of improvement to atomization, that is not the case, you cant actually emulsify a liquid and a gas, you can only emulsify like substances like liquids with another liquid etc. What other manufacturers of carburetors do is they design the booster as a 2 stage so its got lots of vacuum, and to stop the mixture going rich at the top end they reduce the size of the drillings etc so that friction and turbulent flow control the AFR. Doing it this way reduces changes to AFR from weather changes. A carby thats over reliant on emulsion air is over reactive to weather because the emulsion air is effected by the air pressure of the day. If you dont use it it doesnt screw it up.
Holley is a hotrodders carby but its not the best carby for someone who is seeking more.
