In a hypothetical case, let's say we have a 360 LA engine with 11.0:1 compression and a camshaft with .258-degrees of duration at .050-inch lift. Right off the bat, according to the carb selection charge at www.barrygrant.com, we can see a Road Demon 725-cfm vacuum secondary carb would be too small. On the other hand, a Mighty Demon 750-cfm mechanical carb would be ideal. Always get the manufacturer's suggestion when choosing a carb.
Air HeadsFinally, no fuel system is complete without placing some thought into the air that enters the carb. A quality air filter is a must, and advancements in filtration technology have made the air filter welcome on any performance engine due to its increased air-flow. Tests have proven that the right air filter shows negligible decreases in horsepower on the dyno.
Fuel PumpsWhether to use a mechanical or electric fuel pump depends on personal preference, and the demands that will be placed on the fuel pump. In the past, the prevailing thought was that you must use an electric pump for performance applications. Depending on how much performance you are looking for, that is true. But with the advancements made in fuel pump technology, a mechanical is now a viable option when a certain amount of performance is desired. Another consideration when using a high-volume pump is a regulator. If a fuel pump delivers more than 7 1/2 psi, it will overpower the needle and seat, and flood the carb. A regulator is an adjustable device that plumbs in the fuel system after the pump, and regulates the fuel pressure to the carb. Again, consult the manufacturer for their recommendations. If you do use an electric fuel pump, be sure to use a relay in the electrical system to ensure the pump is provided with the proper voltage in order to maintain proper fuel flow.