The A/F ratio should remain flat with respect to RPM. That is, you want 12.7 ish from the stall RPM of your converter to the shift point or trap RPM at WOT. Carburetors are proportional fuel air mixers, so they want to do this, and it would be a challenge to make a properly sized carb do any different. A carburetor can compensate for changes in air density whether changed by barometric pressure (altitude) or temperature up to a point. If you race at sea level, you might find that a jet change might help in Denver, but that's a 5000 foot difference (on the other hand, the car might perform similarly on a cold day in Denver and a scorcher in San Diego). If you are looking to run competitively at your local track, FIND THE JET COMBO THAT MAKES YOUR CAR FASTEST ON A TYPICAL DAY (70 degrees or so), don't get too hung up on A/F numbers. The car will go a little slower if it's hotter, and pick up a bit if it's cooler. This is where keeping notes helps. Most tracks have a weather station that reports temperature and barometer values if not density altitude directly (or call ATIS at the nearest airport). It's the density altitude that matters, that's literally the amount of air available to the engine. Note this on your time slips and you can build a database which will predict how the car will perform at any given DA. The more data points, the more accurately you can predict. But if you change the jets, you have to start over with the notes, because it's literally a different car. Most bracket racers I know make engine and chassis changes in the off season and try to keep the car exactly the same once points start counting. Build a car, any car, and learn how to drive it the same each run, and know what it'll do based on weather. A 17 second car with a driver that cuts a consistent light can and commonly does beat a 9 second car a driver can't drive the same way twice.