Holley and Weber both manufacture aftermarket carburetors that increase the performance of you car. The only downside of these carburetors is that they are really expensive but it is worth it.
Some of these mods can be done with of the shelf parts but the majority of the mods will need a bit of hands on work.
Here is the list of modifications that can be done to a carburetor;
- More pumps
- Center firing jets
- Make the second set of butterflies open when first set is 1/4 open
- Change butterfly shafts to smaller for less resistance
- Lower the boosters for more throttle response
- Thinner butterfly valve
- Smooth the inside of the carby barrels
There are many more modifications that will be updated as people are experimenting with new ideas and designs to increase the performance of a standard factory car.
Another option is to research and ask local mechanics or car enthusiasts about which carburetors can be bolted straight onto your car with no modifications. This is a very effective way to increase the performance of your car seeing that putting a V6 or V8 carby on 4 cylinder car, the amount of fuel and air increase is huge.