Well to begin with holley's are what is called a modular carb and is of totally different design and function than the edelbrock which is really just an aftermarket carter afb with some updates. the edelbrock is simpler to calibrate but the holley will probably give you an edge over it if your engine combination is right. personally on a stock engine I wouldn't use a double pumper. I would go for a vacuum secondary holley or stick with the edelbrock if its the right cfm. Doulbe pumpers get crappy gas mileage on the street due to its mechanical secondaries and its double accelerator pumps(hence the name double pumper). A smaller cfm vacuum secondary single accelerator pump holley with the right discharge boosters will out perform a double pumper of larger cfm on a good street engine.