Originally Posted by The Jet
In my race club we run 250 6 cylinders they are bored out to 4 inch with small block chevy pistons crowder rods roller rockers solid cam and our club rule is a one barrel carb 292 rochester any one know how to get more air flow we can drill out jets but also need air flow to match thanks the jet
In the olden days, this was always a point of contention with the tech inspectors.
Be careful introducing extra air (I call it 'bypass' air) through the intake manifold, like by opening up a vacuum port used for power brakes, for instance. This will make some cylinders run leaner than others- possibly to the point of damaging the engine.
If at all possible, be sure to introduce the air as close to the carb as you can, else you may run a cylinder(s) lean. You can also use individual orifices located in each cylinder's runner to equalize the air going into the engine and jet it up to compensate. This will work OK but it's better to add air closer to the carb so the air mixes better w/the fuel before entering the combustion chamber.
One thing that was done when this was hidden was to use hollow idle mixture screws. In some cases the entire idle circuit was reworked, even to the point where larger idle screws were made so a bigger hole could be drilled in them.
Hollow carb studs are another pathway. Now, if this isn't something that has to be hidden from view, you can use a spacer w/holes, slotted gaskets, etc. But the idea is to keep the extra air close to the carb if possible.