Just remember what an engine really is. An air pump. You can only put in as much air as you can get out. Regardless of the cfm rating of the carb. Rating does no mean actual flowing that much unless you are driving at max RPM, high lift, long duration cam, head work etc...Thats why the cylinder head is the biggest restriction to air flow.. When you put headers on the engine if it is tuned correctly, it tends to run a little lean. That is why you usually get an increase in mpg. the next step is to play with jetting to get the correct a/f mixture again. Put a larger carb on and now the camshaft / and cylinder head is the restriction. Just think of a funnel. No matter how large the opening is you can only flow what small end allows out. For normal, legal speed driving you will be running mainly about 2-3,000 rpm. You don't need a very large carb to be efficient in that rpm range. So the question is, economical turn key ,no fuss reliability or the constant fiddling and tweeking required with a high RPM driving style. Real race cars are for the strip and street cars are for the street . Thats why we have toys. To play with when we want to, not when we have to, to provide daily trans port for work, family, etc...The smaller the carb, the less money you have to spend to make it efficient.
Personal preference is the Edelbrock Thunder series AVS " adjustable air valve " 750cfm #1806. No below thw foat fuel leaks like the Holleys , easy to adjust secondary air valve. Factory adjustment and jetting will be very close to ideal. Turn the key and drive....
